Sonic bought himself a chili dog and juice. He walked away for 10 minutes, and during that time, Eggman added some cat potion to his juice and left. Then Sonic came and drank the juice and ate the chili dog. And he felt himself transform into cat. And after a few minutes turned into a cat.

"W-what happened and why am I a cat? Meow. It's probably Eggman's tricks again. H-how I hate him meow! Always trying to mess things up for me. That meow... That meow... That Stupid Egghead. I think you're definitely going to get me soon. Meow"