Ok, so, it has been very hard to decide, since all four monsters are very funny and they make me wonder what on earth was their creator smoking at the time..
First the vampire frog. The first thing I did when I saw it was to nearly choke with my coffee because of laughter. I'm not sure whether that's because of the plain weirdness of that combination or the fact that it's supposed to look menacing and fails soooo bad.
Got to give credit to the Flumph for being a lawful good floating octopus whose eyes seem to come out of its mouth (I wonder how it smites evil)
Also the duckbunny that seems to hunt in packs by daytime (must be really hard to run with those feet so does it dive for fish in the water? Isn't its fur soaking wet then? No wonder it has that annoyed look)
Still, the gelatinous cube would be exactly what I would choose for this competition. At least the other three were some sort of animals and at least a small amount of brain effort was put into creating them... but this.. this large piece of green jelly that devours people for unknown reasons wins cake
So, the grand winner is
Razzorman with the gelatinous cube.