Chalkzone

ChalkZone is an American animated television series created by Bill Burnettand Larry Huber for Nickelodeon. The series follows Rudy Tabootie, an elementary school student whose magic chalk allows him into the ChalkZone, an alternate dimension where everything drawn on a blackboard and erased becomes real. The show concentrates on the adventures of Rudy, his sidekick Snap, and classmate Penny Sanchez within the zone.

Skrawl's Brain (Season 3, Episode 10)
Skrawl aims to hypnotize everyone in ChalkZone with a giant brain. But the brain turns against him and hypnotizes everyone into thinking they're chickens.