 It is revealed in the season three episode "The Mummy in The Maze" that Booth suffers from coulrophobia.When traveling through a haunted house, Booth is frightened of an evil clown mannequin; Brennan is bewildered by his behavior and Booth feels ashamed when he purposely avoids walking by the mannequin.In season two he shoots a large plastic clown head on an ice cream truck, annoyed with the music.