ismejavati

1. to ridicule; to make fun of; to mock
   Deca su ga ismejavala zbog naočara. — The kids made fun of him because of his glasses.
   Nemoj da ismejavaš tuđe greške. — Don't mock other people's mistakes.

Takes the accusative (ismejavati koga), whereas rugati se and podsmevati se take the dative.