too many forms of this guy, but thats okay.. XD

if you're curious about the lore reasoning behind this:
Error is a glitched chao, and his data / coding is unstable. This leads to corruptions of himself like these, which can happen at random. It's possible a corruption can even split off from himself and become it's own thing.

2013 Error typically happens when his programming freaks out and attempts to load an older codebase, leading to him reverting to his old design.

Gaia happens when he is exposed to high amounts of Gaia energy, a-la the Werehog from Sonic Unleashed

Disk Read Error happens when his data corrupts too far, leading to errors in his rendering. This causes him to become inverted in both personality & looks.

Error Code form appears when he is deeply in tune with the music he is creating or listening to. Seeing this form means he's in a real good mood, and is in his zone. One of the only positive corruptions he has, really.