Maybe you could make the hat a bit taller. And as JustinGameDesing said, some disgusting background would make this look even better. Well done, I have to fave it(it has some weird kind of charm I really like).

The one piece of feedback I can offer is that it seems unlikely that a fungus creature would appear in a pure white environment, but you've got him AAed to that color, so it's clearly what you intended.