They are seen as small, square rocks, with a few cracks in them and are grey coloured. The blocks do not seem to be pointed and look blunt.
Crumbling rocks appear in Hot Air 2, on level 8: Drill Bill. Crumbling blocks like all hazards in the Hot Air series kill the hot air balloon on contact.
They player has to maneuver through them as they are placed around like a tunnel. This is difficult as there is not much space. A few seconds after entering the tunnel of blocks, Drill Bill will begin to come down, causing each block it comes in contact with to crumble. They appear only on this level, and are a complete replica of the crumbling rocks from Frost Bite 1.
The blocks are small-sized, pointed and are shaded with a light colour of grey with a few straight cracks in them.
Crumbling blocks appear in Hot Air Jr at level six. The crumbling blocks in this game will not pop Hot Air Jr on contact. Instead, the balloon will safely bounce off the blocks. However, the blocks will trap him and try to prevent him from reaching stars or the ending pad. The only way to break them is to use floating mines to explode them. The player needs good mouse control to maneuver the mine and explode the blocks.