This one will just never die. It was cute when the fear was first revealed in season two's "Everybody Loves a Clown."
Then the whole thing was pushed to absurd new heights with season seven's “Plucky Pennywhistle’s Magical Menagerie." Sam getting his ass kicked by two homicidal clowns? His personal nightmare come true. The whole thing ended up being totally worth it after seeing Sam covered in glitter in the end. Too priceless for words!
After seemingly conquering his fear at the end of that episode, Sam's fear rears it's head one more ugly time in season eleven's "Plush." Although, instead of a running joke, Sam bravely overcomes his intense fear to save the day. It was a real character defining moment!
Personally, I'm hoping the clown thing is over. But I'm sure some writer will jump at the chance at going there again. Fans love it too much.