diff --git a/js/game.js b/js/game.js
index 28ccaee..542729a 100644
--- a/js/game.js
+++ b/js/game.js
@@ -1025,6 +1025,7 @@ export class Level {
 
                     // Bump tiles that we're even attempting to move into; this mostly reveals
                     // invisible walls, blue floors, etc.
+                    // XXX how to guarantee this only happens once...
                     if (tile.type.on_bump) {
                         tile.type.on_bump(tile, this, actor);
                     }
diff --git a/js/tiletypes.js b/js/tiletypes.js
index ad5dcc4..a505606 100644
--- a/js/tiletypes.js
+++ b/js/tiletypes.js
@@ -892,6 +892,18 @@ const TILE_TYPES = {
             ice_block: true,
             frame_block: true,
         },
+        on_bump(me, level, other) {
+            // Fireballs melt ice blocks on regular floor
+            // XXX what if i'm in motion?
+            if (other.type.name === 'fireball') {
+                let terrain = me.cell.get_terrain();
+                if (terrain.type.name === 'floor') {
+                    level.remove_tile(me);
+                    level.transmute_tile(terrain, 'water');
+                    // FIXME splash?
+                }
+            }
+        },
     },
     frame_block: {
         // TODO directional, obviously