Saturday Nigh Live alum and Tonight Show host Jimmy Fallon is known for his impersonation skills. From Tom Petty to Neil Young to the Bee Gees, Fallon loves getting inside some of the most creative minds in the world. And sometimes he just likes to annoy them.

Take comedy legend Bill Cosby, who appeared on The Tonight Show this week. Cosby has noticed that Fallon seems to enjoy imitating him and he’s not too fond of the homage. That didn’t stop Fallon from doing his best Bill Cosby-walk behind the comedian. That’s just bad manners. And hilarious.

Watch The Tonight Show Starring Jimmy Fallon weekdays at 3E/12P on Much.