Malcolm was a very forgettable character on the show, and he was actually played by David Arquette who was dating Courtney Cox at the time. Whom he later married and divorced.

He actually played a stalker guy who had dated Ursula and was obsessed her but ends up accidentally following her sister Phoebe because they were twins.

Phoebe dumbly agrees to date him and they eventually break up when she realizes he’s really just in love with Ursula and can’t really give up the stalking.