Shlocko

Schlocko the Clown appears in "Cheer Up Candace." Phineas and Ferb hire Schlocko to give Candace a makeover in an attempt to cheer her up. Not surprisingly, the makeover ends up making her look like a clown, making Phineas and Ferb doubt hiring him in the first place.

Much like Harpo Marx, Schlocko never speaks and communicates only by honking a horn.