diff --git a/LEGO1/mxdsaction.cpp b/LEGO1/mxdsaction.cpp
index a62ecfd3..32bc4f0d 100644
--- a/LEGO1/mxdsaction.cpp
+++ b/LEGO1/mxdsaction.cpp
@@ -3,13 +3,18 @@
 #include <float.h>
 #include <limits.h>
 
+DECOMP_SIZE_ASSERT(MxDSAction, 0x94)
+
+// GLOBAL OFFSET: LEGO1 0x10101410
+MxU16 g_unkSep = TWOCC(',', ' ');
+
 // OFFSET: LEGO1 0x100ad810
 MxDSAction::MxDSAction()
 {
   this->m_flags = 32;
   this->m_startTime = INT_MIN;
-  this->m_unk7c = NULL;
-  this->m_unk80 = 0;
+  this->m_unkData = NULL;
+  this->m_unkLength = 0;
   this->m_duration = INT_MIN;
   this->m_loopCount = -1;
 
@@ -39,7 +44,7 @@ MxDSAction::MxDSAction()
 // OFFSET: LEGO1 0x100ada80
 MxDSAction::~MxDSAction()
 {
-  delete this->m_unk7c;
+  delete[] this->m_unkData;
 }
 
 // OFFSET: LEGO1 0x100adaf0
@@ -55,7 +60,7 @@ void MxDSAction::CopyFrom(MxDSAction &p_dsAction)
   this->m_direction.CopyFrom(p_dsAction.m_direction);
   this->m_up.CopyFrom(p_dsAction.m_up);
 
-  FUN_100ADE60(p_dsAction.m_unk80, p_dsAction.m_unk7c);
+  AppendData(p_dsAction.m_unkLength, p_dsAction.m_unkData);
   this->m_unk84 = p_dsAction.m_unk84;
   this->m_unk88 = p_dsAction.m_unk88;
   this->m_omni = p_dsAction.m_omni;
@@ -78,7 +83,7 @@ MxU32 MxDSAction::GetSizeOnDisk()
 {
   MxU32 totalSizeOnDisk;
 
-  totalSizeOnDisk = MxDSObject::GetSizeOnDisk() + 90 + this->m_unk80;
+  totalSizeOnDisk = MxDSObject::GetSizeOnDisk() + 90 + this->m_unkLength;
   this->m_sizeOnDisk = totalSizeOnDisk - MxDSObject::GetSizeOnDisk();
 
   return totalSizeOnDisk;
@@ -116,11 +121,11 @@ void MxDSAction::Deserialize(char **p_source, MxS16 p_unk24)
   this->m_up[2] = *(double*) *p_source;
   *p_source += sizeof(double);
 
-  MxU16 extralen = *(MxU16*) *p_source;
+  MxU16 unkLength = *(MxU16*) *p_source;
   *p_source += sizeof(MxU16);
-  if (extralen) {
-    FUN_100ADE60(extralen, *p_source);
-    *p_source += extralen;
+  if (unkLength) {
+    AppendData(unkLength, *p_source);
+    *p_source += unkLength;
   }
 }
 
@@ -181,14 +186,14 @@ void MxDSAction::MergeFrom(MxDSAction &p_dsAction)
     this->m_up[2] = p_dsAction.m_up[2];
 
   // TODO
-  if (p_dsAction.m_unk80 &&
-      p_dsAction.m_unk7c &&
-      *p_dsAction.m_unk7c &&
-      !strncmp("XXX", (const char*) p_dsAction.m_unk7c, 3))
-  {
-    delete this->m_unk7c;
-    this->m_unk80 = 0;
-    FUN_100ADE60(p_dsAction.m_unk80, p_dsAction.m_unk7c);
+  MxU16 unkLength = p_dsAction.m_unkLength;
+  char *unkData = p_dsAction.m_unkData;
+  if (unkLength && unkData) {
+    if (!this->m_unkData || !strncmp("XXX", this->m_unkData, 3)) {
+      delete[] this->m_unkData;
+      this->m_unkLength = 0;
+      AppendData(unkLength, unkData);
+    }
   }
 }
 
@@ -216,8 +221,30 @@ MxLong MxDSAction::GetCurrentTime()
   return Timer()->GetTime() - this->m_someTimingField;
 }
 
-// OFFSET: LEGO1 0x100ade60 STUB
-void MxDSAction::FUN_100ADE60(MxU16 p_length, void *p_data)
+// OFFSET: LEGO1 0x100ade60
+void MxDSAction::AppendData(MxU16 p_unkLength, const char *p_unkData)
 {
-  // TOOD
+  if (this->m_unkData == p_unkData || !p_unkData)
+    return;
+
+  if (this->m_unkLength) {
+    char *concat = new char[p_unkLength + this->m_unkLength + sizeof(g_unkSep)];
+    memcpy(concat, this->m_unkData, this->m_unkLength);
+
+    *(MxU16*) &concat[this->m_unkLength] = g_unkSep;
+    memcpy(&concat[this->m_unkLength + sizeof(g_unkSep)], p_unkData, p_unkLength);
+
+    this->m_unkLength += p_unkLength + sizeof(g_unkSep);
+    delete[] this->m_unkData;
+    this->m_unkData = concat;
+  }
+  else {
+    char *copy = new char[p_unkLength];
+    this->m_unkData = copy;
+
+    if (copy) {
+      this->m_unkLength = p_unkLength;
+      memcpy(copy, p_unkData, p_unkLength);
+    }
+  }
 }
diff --git a/LEGO1/mxdsaction.h b/LEGO1/mxdsaction.h
index 069986bf..a677741c 100644
--- a/LEGO1/mxdsaction.h
+++ b/LEGO1/mxdsaction.h
@@ -40,7 +40,7 @@ class MxDSAction : public MxDSObject
   virtual MxLong GetSomeTimingField(); // vtable+3c;
   virtual MxLong GetCurrentTime(); // vtable+40;
 
-  void FUN_100ADE60(MxU16 p_length, void *p_data);
+  void AppendData(MxU16 p_unkLength, const char *p_unkData);
 
 private:
   MxU32 m_sizeOnDisk;
@@ -51,8 +51,8 @@ class MxDSAction : public MxDSObject
   MxVector3Data m_location;
   MxVector3Data m_direction;
   MxVector3Data m_up;
-  undefined4 *m_unk7c;
-  MxU16 m_unk80;
+  char *m_unkData;
+  MxU16 m_unkLength;
   undefined4 m_unk84;
   undefined4 m_unk88;
   MxOmni* m_omni; // 0x8c
diff --git a/LEGO1/mxdsfile.cpp b/LEGO1/mxdsfile.cpp
index 60f8533e..8bccf914 100644
--- a/LEGO1/mxdsfile.cpp
+++ b/LEGO1/mxdsfile.cpp
@@ -5,8 +5,6 @@
 #define SI_MAJOR_VERSION 2
 #define SI_MINOR_VERSION 2
 
-#define FOURCC(a, b, c, d) (((a) << 0) | ((b) << 8) | ((c) << 16) | ((d) << 24))
-
 // OFFSET: LEGO1 0x100cc4b0
 MxDSFile::MxDSFile(const char *filename, MxULong skipReadingChunks)
 {
diff --git a/LEGO1/mxtypes.h b/LEGO1/mxtypes.h
index 1f0aaac7..fc8d47b5 100644
--- a/LEGO1/mxtypes.h
+++ b/LEGO1/mxtypes.h
@@ -41,4 +41,7 @@ typedef MxU8 MxBool;
 #define FALSE 0
 #endif
 
+#define TWOCC(a, b) (((a) << 0) | ((b) << 8))
+#define FOURCC(a, b, c, d) (((a) << 0) | ((b) << 8) | ((c) << 16) | ((d) << 24))
+
 #endif // MXTYPE_H