A giant crap. If Digimon could get away with that (Sukamon), Pokemon should be able to as well.
I always prefered Numemon. Both made of digital waste, but Numemon is a more adorable, slime-like creature, that looks like Grubber from the Gang Green Gang in Powerpuff Girls. http://images.wikia.com/powerpuff/images/0/0a/Grubber.png
But yeah, a Demon Wall-esque Pokemon, except less demon-y and more wall-y.