Index: exec.c
==================================================================
--- exec.c
+++ exec.c
@@ -46,10 +46,11 @@
 static Value vstack[VSTACKSIZE];
 static int vstackptr;
 static const char*traceprefix;
 static Uint8 current_key;
 static Value quiz_obj;
+static Value traced_obj;
 
 #define Throw(x) (my_error=(x),longjmp(my_env,1))
 #define StackReq(x,y) do{ if(vstackptr<(x)) Throw("Stack underflow"); if(vstackptr-(x)+(y)>=VSTACKSIZE) Throw("Stack overflow"); }while(0)
 #define Push(x) (vstack[vstackptr++]=(x))
 #define Pop() (vstack[--vstackptr])
@@ -156,10 +157,14 @@
 #define animfree free
 
 void objtrash(Uint32 n) {
   Object*o=objects[n];
   if(!o) return;
+  if(n==traced_obj.u && o->generation==traced_obj.t && main_options['t'] && !main_options['e']) {
+    printf("# Object traced at (%d,%d)\n",o->x,o->y);
+    Throw("Object traced");
+  }
   animfree(o->anim);
   if(o->down==VOIDLINK) playfield[o->x+o->y*64-65]=o->up;
   else objects[o->down]->up=o->up;
   if(o->up!=VOIDLINK) objects[o->up]->down=o->down;
   if(!(o->oflags&OF_DESTROYED)) {
@@ -448,11 +453,11 @@
   if(v.t==TY_NUMBER) {
     if(v.u) Throw("Cannot convert non-zero number to object");
     return VOIDLINK;
   } else if(v.t>TY_MAXTYPE) {
     if(v.u>=nobjects || !objects[v.u] || objects[v.u]->generation!=v.t) {
-      if(main_options['t']) printf("Object %lu in generation %lu does not exist\n",(long)v.u,(long)v.t);
+      if(main_options['t']) printf("[Object %lu in generation %lu does not exist]\n",(long)v.u,(long)v.t);
       Throw("Attempt to use a nonexistent object");
     }
     return v.u;
   } else {
     Throw("Cannot convert non-object to object");
@@ -1673,11 +1678,24 @@
   return 0;
 }
 
 const char*init_level(void) {
   if(setjmp(my_env)) return my_error;
-  if(main_options['t']) printf("[Level %d restarted]\n",level_id);
+  if(main_options['t']) {
+    printf("[Level %d restarted]\n",level_id);
+    if(!traced_obj.t) {
+      const char*s;
+      optionquery[1]=Q_traceObject;
+      if(s=xrm_get_resource(resourcedb,optionquery,optionquery,2)) {
+        traced_obj.u=strtol(s,(char**)&s,10);
+        if(*s==':') traced_obj.t=strtol(s+1,0,10);
+        printf("Tracing object <%ld:%ld>\n",(long)traced_obj.u,(long)traced_obj.t);
+      } else {
+        traced_obj.t=TY_FOR;
+      }
+    }
+  }
   memcpy(globals,initglobals,sizeof(globals));
   quiz_obj=NVALUE(0);
   gameover=0;
   changed=0;
   key_ignored=0;

Index: quarks
==================================================================
--- quarks
+++ quarks
@@ -212,6 +212,7 @@
 level
 tracePrefix
 stackProtection
 maxObjects
 traceAll
+traceObject
 

Index: quarks.h
==================================================================
--- quarks.h
+++ quarks.h
@@ -177,10 +177,11 @@
 #define Q_level 178
 #define Q_tracePrefix 179
 #define Q_stackProtection 180
 #define Q_maxObjects 181
 #define Q_traceAll 182
+#define Q_traceObject 183
 static const char*const global_quarks[]={
   "screenWidth",
   "screenHeight",
   "margin",
   "palette",
@@ -359,10 +360,11 @@
   "level",
   "tracePrefix",
   "stackProtection",
   "maxObjects",
   "traceAll",
+  "traceObject",
 0};
 #ifdef HEROMESH_BINDINGS
 static const SDLKey quark_to_key[Q_undo+1-Q_backspace]={
 SDLK_BACKSPACE,
 SDLK_TAB,