And that is true, that's where I first saw it but have since learned that the GIF of Master Belch, from the Super Nintendo game Earthbound, was originally dumped by frankhats. And not just "dumped" (found, posted): it's an animation he made from existing still images. Apparently the Master Belch character comes in multiple slime colors (and has different names).* frankhats found smaller, avatar-sized versions of two types and then turned them into a two-frame animation that loops rapidly and appears to vibrate. He also increased the image size so the pixels are more visible. Nice work, meaning likely to slip out of the author's fingers when passed around the Net.
*"so there's barf, belch, puke, and an even slimier little pile" (based on dump research)