diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index d5a53b164..8c7809b64 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -2,7 +2,7 @@ use nac3core::{
     codegen::{
         classes::{
             ArrayLikeIndexer, ArrayLikeValue, ArraySliceValue, ListValue, NDArrayType,
-            NDArrayValue, RangeValue, UntypedArrayLikeAccessor,
+            NDArrayValue, ProxyType, ProxyValue, RangeValue, UntypedArrayLikeAccessor,
         },
         expr::{destructure_range, gen_call},
         irrt::call_ndarray_calc_size,
@@ -22,7 +22,7 @@ use inkwell::{
     module::Linkage,
     types::{BasicType, IntType},
     values::{BasicValueEnum, PointerValue, StructValue},
-    AddressSpace, IntPredicate,
+    AddressSpace, IntPredicate, OptimizationLevel,
 };
 
 use pyo3::{
@@ -32,6 +32,7 @@ use pyo3::{
 
 use crate::{symbol_resolver::InnerResolver, timeline::TimeFns};
 
+use inkwell::values::IntValue;
 use itertools::Itertools;
 use std::{
     collections::{hash_map::DefaultHasher, HashMap},
@@ -486,13 +487,10 @@ fn format_rpc_arg<'ctx>(
             let buffer = ctx.builder.build_array_alloca(llvm_i8, buffer_size, "rpc.arg").unwrap();
             let buffer = ArraySliceValue::from_ptr_val(buffer, buffer_size, Some("rpc.arg"));
 
-            let ppdata = generator.gen_var_alloc(ctx, llvm_arg_ty.element_type(), None).unwrap();
-            ctx.builder.build_store(ppdata, llvm_arg.data().base_ptr(ctx, generator)).unwrap();
-
             call_memcpy_generic(
                 ctx,
                 buffer.base_ptr(ctx, generator),
-                ppdata,
+                llvm_arg.ptr_to_data(ctx),
                 llvm_pdata_sizeof,
                 llvm_i1.const_zero(),
             );
@@ -528,6 +526,298 @@ fn format_rpc_arg<'ctx>(
     arg_slot
 }
 
+/// Formats an RPC return value to conform to the expected format required by NAC3.
+fn format_rpc_ret<'ctx>(
+    generator: &mut dyn CodeGenerator,
+    ctx: &mut CodeGenContext<'ctx, '_>,
+    ret_ty: Type,
+) -> Option<BasicValueEnum<'ctx>> {
+    // -- receive value:
+    // T result = {
+    //   void *ret_ptr = alloca(sizeof(T));
+    //   void *ptr = ret_ptr;
+    //   loop: int size = rpc_recv(ptr);
+    //   // Non-zero: Provide `size` bytes of extra storage for variable-length data.
+    //   if(size) { ptr = alloca(size); goto loop; }
+    //   else *(T*)ret_ptr
+    // }
+
+    let llvm_i8 = ctx.ctx.i8_type();
+    let llvm_i32 = ctx.ctx.i32_type();
+    let llvm_i8_8 = ctx.ctx.struct_type(&[llvm_i8.array_type(8).into()], false);
+    let llvm_pi8 = llvm_i8.ptr_type(AddressSpace::default());
+
+    let rpc_recv = ctx.module.get_function("rpc_recv").unwrap_or_else(|| {
+        ctx.module.add_function("rpc_recv", llvm_i32.fn_type(&[llvm_pi8.into()], false), None)
+    });
+
+    if ctx.unifier.unioned(ret_ty, ctx.primitives.none) {
+        ctx.build_call_or_invoke(rpc_recv, &[llvm_pi8.const_null().into()], "rpc_recv");
+        return None;
+    }
+
+    let prehead_bb = ctx.builder.get_insert_block().unwrap();
+    let current_function = prehead_bb.get_parent().unwrap();
+    let head_bb = ctx.ctx.append_basic_block(current_function, "rpc.head");
+    let alloc_bb = ctx.ctx.append_basic_block(current_function, "rpc.continue");
+    let tail_bb = ctx.ctx.append_basic_block(current_function, "rpc.tail");
+
+    let llvm_ret_ty = ctx.get_llvm_abi_type(generator, ret_ty);
+
+    let result = match &*ctx.unifier.get_ty_immutable(ret_ty) {
+        TypeEnum::TObj { obj_id, .. } if *obj_id == PrimDef::NDArray.id() => {
+            let llvm_i1 = ctx.ctx.bool_type();
+            let llvm_usize = generator.get_size_type(ctx.ctx);
+
+            // Round `val` up to its modulo `power_of_two`
+            let round_up = |ctx: &mut CodeGenContext<'ctx, '_>,
+                            val: IntValue<'ctx>,
+                            power_of_two: IntValue<'ctx>| {
+                debug_assert_eq!(
+                    val.get_type().get_bit_width(),
+                    power_of_two.get_type().get_bit_width()
+                );
+
+                let llvm_val_t = val.get_type();
+
+                let max_rem = ctx
+                    .builder
+                    .build_int_sub(power_of_two, llvm_val_t.const_int(1, false), "")
+                    .unwrap();
+                ctx.builder
+                    .build_and(
+                        ctx.builder.build_int_add(val, max_rem, "").unwrap(),
+                        ctx.builder.build_not(max_rem, "").unwrap(),
+                        "",
+                    )
+                    .unwrap()
+            };
+
+            // Setup types
+            let (elem_ty, ndims) = unpack_ndarray_var_tys(&mut ctx.unifier, ret_ty);
+            let llvm_elem_ty = ctx.get_llvm_type(generator, elem_ty);
+            let llvm_ret_ty = NDArrayType::new(generator, ctx.ctx, llvm_elem_ty);
+
+            // Allocate the resulting ndarray
+            // A condition after format_rpc_ret ensures this will not be popped this off.
+            let ndarray = llvm_ret_ty.new_value(generator, ctx, Some("rpc.result"));
+
+            // Setup ndims
+            let ndims =
+                if let TypeEnum::TLiteral { values, .. } = &*ctx.unifier.get_ty_immutable(ndims) {
+                    assert_eq!(values.len(), 1);
+
+                    u64::try_from(values[0].clone()).unwrap()
+                } else {
+                    unreachable!();
+                };
+            // Set `ndarray.ndims`
+            ndarray.store_ndims(ctx, generator, llvm_usize.const_int(ndims, false));
+            // Allocate `ndarray.shape` [size_t; ndims]
+            ndarray.create_dim_sizes(ctx, llvm_usize, ndarray.load_ndims(ctx));
+
+            /*
+                ndarray now:
+                  - .ndims: initialized
+                  - .shape: allocated but uninitialized .shape
+                  - .data: uninitialized
+            */
+
+            let llvm_usize_sizeof = ctx
+                .builder
+                .build_int_truncate_or_bit_cast(llvm_usize.size_of(), llvm_usize, "")
+                .unwrap();
+            let llvm_pdata_sizeof = ctx
+                .builder
+                .build_int_truncate_or_bit_cast(
+                    llvm_ret_ty.element_type().size_of().unwrap(),
+                    llvm_usize,
+                    "",
+                )
+                .unwrap();
+            let llvm_elem_sizeof = ctx
+                .builder
+                .build_int_truncate_or_bit_cast(llvm_elem_ty.size_of().unwrap(), llvm_usize, "")
+                .unwrap();
+
+            // Allocates a buffer for the initial RPC'ed object, which is guaranteed to be
+            // (4 + 4 * ndims) bytes with 8-byte alignment
+            let sizeof_dims =
+                ctx.builder.build_int_mul(ndarray.load_ndims(ctx), llvm_usize_sizeof, "").unwrap();
+            let unaligned_buffer_size =
+                ctx.builder.build_int_add(sizeof_dims, llvm_pdata_sizeof, "").unwrap();
+            let buffer_size = round_up(ctx, unaligned_buffer_size, llvm_usize.const_int(8, false));
+
+            let stackptr = call_stacksave(ctx, None);
+            // Just to be absolutely sure, alloca in [i8 x 8] slices to force 8-byte alignment
+            let buffer = ctx
+                .builder
+                .build_array_alloca(
+                    llvm_i8_8,
+                    ctx.builder
+                        .build_int_unsigned_div(buffer_size, llvm_usize.const_int(8, false), "")
+                        .unwrap(),
+                    "rpc.buffer",
+                )
+                .unwrap();
+            let buffer = ctx
+                .builder
+                .build_bitcast(buffer, llvm_pi8, "")
+                .map(BasicValueEnum::into_pointer_value)
+                .unwrap();
+            let buffer = ArraySliceValue::from_ptr_val(buffer, buffer_size, None);
+
+            // The first call to `rpc_recv` reads the top-level ndarray object: [pdata, shape]
+            //
+            // The returned value is the number of bytes for `ndarray.data`.
+            let ndarray_nbytes = ctx
+                .build_call_or_invoke(
+                    rpc_recv,
+                    &[buffer.base_ptr(ctx, generator).into()], // Reads [usize; ndims]. NOTE: We are allocated [size_t; ndims].
+                    "rpc.size.next",
+                )
+                .map(BasicValueEnum::into_int_value)
+                .unwrap();
+
+            // debug_assert(ndarray_nbytes > 0)
+            if ctx.registry.llvm_options.opt_level == OptimizationLevel::None {
+                ctx.make_assert(
+                    generator,
+                    ctx.builder
+                        .build_int_compare(
+                            IntPredicate::UGT,
+                            ndarray_nbytes,
+                            ndarray_nbytes.get_type().const_zero(),
+                            "",
+                        )
+                        .unwrap(),
+                    "0:AssertionError",
+                    "Unexpected RPC termination for ndarray - Expected data buffer next",
+                    [None, None, None],
+                    ctx.current_loc,
+                );
+            }
+
+            // Copy shape from the buffer to `ndarray.shape`.
+            let pbuffer_dims =
+                unsafe { buffer.ptr_offset_unchecked(ctx, generator, &llvm_pdata_sizeof, None) };
+
+            call_memcpy_generic(
+                ctx,
+                ndarray.dim_sizes().base_ptr(ctx, generator),
+                pbuffer_dims,
+                sizeof_dims,
+                llvm_i1.const_zero(),
+            );
+            // Restore stack from before allocation of buffer
+            call_stackrestore(ctx, stackptr);
+
+            // Allocate `ndarray.data`.
+            // `ndarray.shape` must be initialized beforehand in this implementation
+            //   (for ndarray.create_data() to know how many elements to allocate)
+            let num_elements =
+                call_ndarray_calc_size(generator, ctx, &ndarray.dim_sizes(), (None, None));
+
+            // debug_assert(nelems * sizeof(T) >= ndarray_nbytes)
+            if ctx.registry.llvm_options.opt_level == OptimizationLevel::None {
+                let sizeof_data =
+                    ctx.builder.build_int_mul(num_elements, llvm_elem_sizeof, "").unwrap();
+
+                ctx.make_assert(
+                    generator,
+                    ctx.builder.build_int_compare(IntPredicate::UGE,
+                        sizeof_data,
+                        ndarray_nbytes,
+                        "",
+                    ).unwrap(),
+                    "0:AssertionError",
+                    "Unexpected allocation size request for ndarray data - Expected up to {0} bytes, got {1} bytes",
+                    [Some(sizeof_data), Some(ndarray_nbytes), None],
+                    ctx.current_loc,
+                );
+            }
+
+            ndarray.create_data(ctx, llvm_elem_ty, num_elements);
+
+            let ndarray_data = ndarray.data().base_ptr(ctx, generator);
+            let ndarray_data_i8 =
+                ctx.builder.build_pointer_cast(ndarray_data, llvm_pi8, "").unwrap();
+
+            // NOTE: Currently on `prehead_bb`
+            ctx.builder.build_unconditional_branch(head_bb).unwrap();
+
+            // Inserting into `head_bb`. Do `rpc_recv` for `data` recursively.
+            ctx.builder.position_at_end(head_bb);
+
+            let phi = ctx.builder.build_phi(llvm_pi8, "rpc.ptr").unwrap();
+            phi.add_incoming(&[(&ndarray_data_i8, prehead_bb)]);
+
+            let alloc_size = ctx
+                .build_call_or_invoke(rpc_recv, &[phi.as_basic_value()], "rpc.size.next")
+                .map(BasicValueEnum::into_int_value)
+                .unwrap();
+
+            let is_done = ctx
+                .builder
+                .build_int_compare(IntPredicate::EQ, llvm_i32.const_zero(), alloc_size, "rpc.done")
+                .unwrap();
+            ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
+
+            ctx.builder.position_at_end(alloc_bb);
+            // Align the allocation to sizeof(T)
+            let alloc_size = round_up(ctx, alloc_size, llvm_elem_sizeof);
+            let alloc_ptr = ctx
+                .builder
+                .build_array_alloca(
+                    llvm_elem_ty,
+                    ctx.builder.build_int_unsigned_div(alloc_size, llvm_elem_sizeof, "").unwrap(),
+                    "rpc.alloc",
+                )
+                .unwrap();
+            let alloc_ptr =
+                ctx.builder.build_pointer_cast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").unwrap();
+            phi.add_incoming(&[(&alloc_ptr, alloc_bb)]);
+            ctx.builder.build_unconditional_branch(head_bb).unwrap();
+
+            ctx.builder.position_at_end(tail_bb);
+            ndarray.as_base_value().into()
+        }
+
+        _ => {
+            let slot = ctx.builder.build_alloca(llvm_ret_ty, "rpc.ret.slot").unwrap();
+            let slotgen = ctx.builder.build_bitcast(slot, llvm_pi8, "rpc.ret.ptr").unwrap();
+            ctx.builder.build_unconditional_branch(head_bb).unwrap();
+            ctx.builder.position_at_end(head_bb);
+
+            let phi = ctx.builder.build_phi(llvm_pi8, "rpc.ptr").unwrap();
+            phi.add_incoming(&[(&slotgen, prehead_bb)]);
+            let alloc_size = ctx
+                .build_call_or_invoke(rpc_recv, &[phi.as_basic_value()], "rpc.size.next")
+                .unwrap()
+                .into_int_value();
+            let is_done = ctx
+                .builder
+                .build_int_compare(IntPredicate::EQ, llvm_i32.const_zero(), alloc_size, "rpc.done")
+                .unwrap();
+
+            ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
+            ctx.builder.position_at_end(alloc_bb);
+
+            let alloc_ptr =
+                ctx.builder.build_array_alloca(llvm_pi8, alloc_size, "rpc.alloc").unwrap();
+            let alloc_ptr =
+                ctx.builder.build_bitcast(alloc_ptr, llvm_pi8, "rpc.alloc.ptr").unwrap();
+            phi.add_incoming(&[(&alloc_ptr, alloc_bb)]);
+            ctx.builder.build_unconditional_branch(head_bb).unwrap();
+
+            ctx.builder.position_at_end(tail_bb);
+            ctx.builder.build_load(slot, "rpc.result").unwrap()
+        }
+    };
+
+    Some(result)
+}
+
 fn rpc_codegen_callback_fn<'ctx>(
     ctx: &mut CodeGenContext<'ctx, '_>,
     obj: Option<(Type, ValueEnum<'ctx>)>,
@@ -663,63 +953,14 @@ fn rpc_codegen_callback_fn<'ctx>(
     // reclaim stack space used by arguments
     call_stackrestore(ctx, stackptr);
 
-    // -- receive value:
-    // T result = {
-    //   void *ret_ptr = alloca(sizeof(T));
-    //   void *ptr = ret_ptr;
-    //   loop: int size = rpc_recv(ptr);
-    //   // Non-zero: Provide `size` bytes of extra storage for variable-length data.
-    //   if(size) { ptr = alloca(size); goto loop; }
-    //   else *(T*)ret_ptr
-    // }
-    let rpc_recv = ctx.module.get_function("rpc_recv").unwrap_or_else(|| {
-        ctx.module.add_function("rpc_recv", int32.fn_type(&[ptr_type.into()], false), None)
-    });
+    let result = format_rpc_ret(generator, ctx, fun.0.ret);
 
-    if ctx.unifier.unioned(fun.0.ret, ctx.primitives.none) {
-        ctx.build_call_or_invoke(rpc_recv, &[ptr_type.const_null().into()], "rpc_recv");
-        return Ok(None);
-    }
-
-    let prehead_bb = ctx.builder.get_insert_block().unwrap();
-    let current_function = prehead_bb.get_parent().unwrap();
-    let head_bb = ctx.ctx.append_basic_block(current_function, "rpc.head");
-    let alloc_bb = ctx.ctx.append_basic_block(current_function, "rpc.continue");
-    let tail_bb = ctx.ctx.append_basic_block(current_function, "rpc.tail");
-
-    let ret_ty = ctx.get_llvm_abi_type(generator, fun.0.ret);
-    let need_load = !ret_ty.is_pointer_type();
-    let slot = ctx.builder.build_alloca(ret_ty, "rpc.ret.slot").unwrap();
-    let slotgen = ctx.builder.build_bitcast(slot, ptr_type, "rpc.ret.ptr").unwrap();
-    ctx.builder.build_unconditional_branch(head_bb).unwrap();
-    ctx.builder.position_at_end(head_bb);
-
-    let phi = ctx.builder.build_phi(ptr_type, "rpc.ptr").unwrap();
-    phi.add_incoming(&[(&slotgen, prehead_bb)]);
-    let alloc_size = ctx
-        .build_call_or_invoke(rpc_recv, &[phi.as_basic_value()], "rpc.size.next")
-        .unwrap()
-        .into_int_value();
-    let is_done = ctx
-        .builder
-        .build_int_compare(inkwell::IntPredicate::EQ, int32.const_zero(), alloc_size, "rpc.done")
-        .unwrap();
-
-    ctx.builder.build_conditional_branch(is_done, tail_bb, alloc_bb).unwrap();
-    ctx.builder.position_at_end(alloc_bb);
-
-    let alloc_ptr = ctx.builder.build_array_alloca(ptr_type, alloc_size, "rpc.alloc").unwrap();
-    let alloc_ptr = ctx.builder.build_bitcast(alloc_ptr, ptr_type, "rpc.alloc.ptr").unwrap();
-    phi.add_incoming(&[(&alloc_ptr, alloc_bb)]);
-    ctx.builder.build_unconditional_branch(head_bb).unwrap();
-
-    ctx.builder.position_at_end(tail_bb);
-
-    let result = ctx.builder.build_load(slot, "rpc.result").unwrap();
-    if need_load {
+    if !result.is_some_and(|res| res.get_type().is_pointer_type()) {
+        // An RPC returning an NDArray would not touch here.
         call_stackrestore(ctx, stackptr);
     }
-    Ok(Some(result))
+
+    Ok(result)
 }
 
 pub fn attributes_writeback(
diff --git a/nac3core/src/codegen/classes.rs b/nac3core/src/codegen/classes.rs
index 52e9cca01..9ebac518e 100644
--- a/nac3core/src/codegen/classes.rs
+++ b/nac3core/src/codegen/classes.rs
@@ -1404,7 +1404,7 @@ impl<'ctx> NDArrayValue<'ctx> {
 
     /// Returns the double-indirection pointer to the `data` array, as if by calling `getelementptr`
     /// on the field.
-    fn ptr_to_data(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
+    pub fn ptr_to_data(&self, ctx: &CodeGenContext<'ctx, '_>) -> PointerValue<'ctx> {
         let llvm_i32 = ctx.ctx.i32_type();
         let var_name = self.name.map(|v| format!("{v}.data.addr")).unwrap_or_default();