Nouns

(n)antic, joke, prank, trick, caper, put-ona ludicrous or grotesque act done for fun and amusement

Verbs

(v)clown, clown around, anticact as or like a clown

Adjectives

(s)antic, fantastic, fantastical, grotesqueludicrously odd“Hamlet's assumed antic disposition”, “fantastic Halloween costumes”, “a grotesque reflection in the mirror”