diff -pruN slashem-0.0.7E7F1-official-release/include/extern.h slashem-0.0.7E7F1-box/include/extern.h
--- slashem-0.0.7E7F1-official-release/include/extern.h	2005-07-02 09:24:44.000000000 +0200
+++ slashem-0.0.7E7F1-box/include/extern.h	2005-11-24 17:49:27.000000000 +0100
@@ -949,6 +949,7 @@ E int FDECL(pick_lock, (struct obj **));
 E int NDECL(doforce);
 E boolean FDECL(boxlock, (struct obj *,struct obj *));
 E boolean FDECL(doorlock, (struct obj *,int,int));
+E void FDECL(chest_shatter_msg, (struct obj *));
 E int NDECL(doopen);
 E int NDECL(doclose);
 E int FDECL(artifact_door, (int,int));
diff -pruN slashem-0.0.7E7F1-official-release/src/lock.c slashem-0.0.7E7F1-box/src/lock.c
--- slashem-0.0.7E7F1-official-release/src/lock.c	2005-07-02 09:24:44.000000000 +0200
+++ slashem-0.0.7E7F1-box/src/lock.c	2005-11-24 17:57:24.000000000 +0100
@@ -21,7 +21,6 @@ STATIC_VAR NEARDATA struct xlock_s {
 
 STATIC_DCL const char *NDECL(lock_action);
 STATIC_DCL boolean FDECL(obstructed,(int,int));
-STATIC_DCL void FDECL(chest_shatter_msg, (struct obj *));
 
 boolean
 picking_lock(x, y)
@@ -1126,7 +1125,7 @@ int x, y;
 	return res;
 }
 
-STATIC_OVL void
+void
 chest_shatter_msg(otmp)
 struct obj *otmp;
 {
diff -pruN slashem-0.0.7E7F1-official-release/src/sit.c slashem-0.0.7E7F1-box/src/sit.c
--- slashem-0.0.7E7F1-official-release/src/sit.c	2005-07-02 09:24:44.000000000 +0200
+++ slashem-0.0.7E7F1-box/src/sit.c	2005-11-24 18:01:48.000000000 +0100
@@ -39,7 +39,7 @@ int
 dosit()
 {
 	static const char sit_message[] = "sit on the %s.";
-	register struct trap *trap;
+	register struct trap *trap = t_at(u.ux, u.uy);
 	register int typ = levl[u.ux][u.uy].typ;
 
 
@@ -60,16 +60,77 @@ dosit()
 	    goto in_water;
 	}
 
-	if(OBJ_AT(u.ux, u.uy)) {
+	if (!u.utrap && trap && (trap->ttyp == SPIKED_PIT || trap->ttyp == PIT))
+	  {
+	    You("sit at the edge of the %spit%s.",
+		(trap->ttyp == SPIKED_PIT) ? "spiked " : "",
+		(Hallucination) ? " and contemplate the meaning of life." : "");
+	  } else if(OBJ_AT(u.ux, u.uy)) {
+	    
 	    register struct obj *obj;
 
 	    obj = level.objects[u.ux][u.uy];
 	    You("sit on %s.", the(xname(obj)));
 	    if (!(Is_box(obj) || objects[obj->otyp].oc_material == CLOTH))
-		pline("It's not very comfortable...");
-
-	} else if ((trap = t_at(u.ux, u.uy)) != 0 ||
-		   (u.utrap && (u.utraptype >= TT_LAVA))) {
+	      pline("It's not very comfortable...");
+	    
+	    /*
+	      Heavy monsters (dragons, titanotheres, etc.) have an
+	      80% chance of breaking open a box by sitting on it.
+	    */
+	    if(Is_box(obj) && youmonst.data->cwt >= 2600 && rn2(5)) {
+	      struct monst *shkp;
+	      boolean costly = (*u.ushops && costly_spot(u.ux, u.uy));
+	      long loss = 0L;
+	      boolean otrp = obj->otrapped;
+	      struct obj *otmp;
+	      
+	      
+	      shkp = costly ? shop_keeper(*u.ushops) : 0;
+	      
+	      
+#if 0
+	      /*
+		This is what should happen, but doesn't, because
+		we don't know what to call the player's "seat".
+		Also, it seems odd that poison needles should be
+		able to miss such a big target!
+	      */
+	      if (otrp) (void) chest_trap(kickobj, LEG, FALSE);
+#endif
+	      
+	      
+	      pline("%s shatters under your weight!", The(xname(obj)));
+	      
+	      /* Put the contents on ground at the hero's feet. */
+	      while ((otmp = obj->cobj) != 0) {
+                obj_extract_self(otmp);
+                if(!rn2(3) || otmp->oclass == POTION_CLASS) {
+		  chest_shatter_msg(otmp);
+		  if (costly)
+		    loss += stolen_value(otmp, u.ux, u.uy,
+					 (boolean)shkp->mpeaceful, TRUE, TRUE);
+		  if (otmp->quan == 1L) {
+		    obfree(otmp, (struct obj *) 0);
+		    continue;
+		  }
+		  useup(otmp);
+                }
+                place_object(otmp, u.ux, u.uy);
+                stackobj(otmp);
+	      }
+	      
+	      
+	      if (costly)
+                loss += stolen_value(obj, u.ux, u.uy,
+				     (boolean)shkp->mpeaceful, TRUE, TRUE);
+	      if(loss)
+		You("owe %ld %s for objects destroyed.", loss, currency(loss));
+	      delobj(obj);
+	    }
+	    
+	    
+	  } else if (trap || (u.utrap && (u.utraptype >= TT_LAVA))) {
 
 	    if (u.utrap) {
 		exercise(A_WIS, FALSE);	/* you're getting stuck longer */