It was actually pretty cute and took place in the darker Saturday morning cartoon universe but with Shadow.
Sonic started to inflate when some balloon popped, eventually Shadow and Sally started inflating too because there were bee robots could inflate them. Eventually getting poked reverted the inflated back to normal.
I've been trying to find it on DA agaain anyone else seen it?
The artist took that down a while back, I think. Was posted under Sonic-Loser at the time.