Stuppy is a combination of a glitch/meme.
Stuppy is a glitch on the Sporum when you replace this images code http://i.neoseeker.com/mgv/534576-Albatross/576/95/poo_brain_horse_display.gif\
The outcome is a rather pretty yellow flower which causes Stuppy for no reason known.
with anything else like this. http://i.neoseeker.com/mgv/534576-Albatross/576/95/insert_thing_here_horse_display.gif
It was created on the RPtroll monarchy thread on page 2.
The creator of it is titaniccreatures and sakumoto. Titanic posted the origanal image, and Sakumoto edited it. It was then named Stuppy by titaniccreatures.