Don’t talk bad about 50 Cent… especially when he’s standing behind you.

The hip-hop mogul appeared on Jimmy Kimmel Live this week… and stuck around to pull some pranks on a few unsuspecting people on the street afterward.

Kimmel staff interviewed random people on Hollywood Blvd., asking them if they feel 50 is the greatest rapper of all-time. After disagreeing, Fif opened a door behind them and confronted them.

Hey… 50 Cent is behind you.