diff --git a/include/common_structs.h b/include/common_structs.h
index d51945b7d2..bb260c216b 100644
--- a/include/common_structs.h
+++ b/include/common_structs.h
@@ -787,7 +787,7 @@ typedef struct EffectInstance {
     /* 0x00 */ s32 flags;
     /* 0x04 */ s32 effectIndex;
     /* 0x08 */ s32 totalMatricies;
-    /* 0x0C */ void* unk_0C;
+    /* 0x0C */ Vec4f* unk_0C;          // Correct Type?
     /* 0x10 */ struct Effect* effect;
 } EffectInstance;
 
@@ -1723,10 +1723,4 @@ typedef struct {
     /* 0x11630 */ Matrix4s matrixStack[0x200];
 } DisplayContext; // size = 0x19630
 
-// Size and purpose unknown
-typedef struct ScriptOwner {
-    /* 0x000 */ u16 unk_00; // ActorID??
-    /* 0x003 */ u8 unk_03; // ActorPartIndex??
-} ScriptOwner;
-
 #endif
diff --git a/src/code_1AF120.c b/src/code_1AF120.c
index dfad65a6d8..c7472eb317 100644
--- a/src/code_1AF120.c
+++ b/src/code_1AF120.c
@@ -13,4 +13,15 @@ ApiStatus GetDamageIntensity(ScriptInstance* script, s32 isInitialCall) {
     return ApiStatus_DONE2;
 }
 
-INCLUDE_ASM(s32, "code_1AF120", ActorAddMovePos);
+// TODO: Rename to AddEffectOffset
+ApiStatus ActorAddMovePos(ScriptInstance* script, s32 isInitialCall) {
+    Bytecode* args = script->ptrReadPos;
+    EffectInstance* effect = get_variable(script, *args++);
+
+    // TODO: Figure out the actual type of unk_0C
+    effect->unk_0C->y += get_variable(script, *args++);
+    effect->unk_0C->z += get_variable(script, *args++);
+    effect->unk_0C->yaw += get_variable(script, *args++);
+
+    return ApiStatus_DONE2;
+}