Cheezo, Bippo & Dippo

The Clowns (who, to my knowledge were never named) were the main villains of the slasher-movie Clownhouse, a film fairly unique in the genre for not relying too heavily on gore or violence but on the suspense and horror made popular with the original Halloween.

These three villains were escapees from a mental institution who happened to escape during the time a circus was in town - they proceeded to murder three clowns and take their costumes as their own.

By fate or coincedence Cassey, the child protagonist of the film, encounters them when he is taken to the circus by his brothers to try and combat his fear of clowns (which is a geniune phobia to him) - unfortunately for them the three "clowns" decide to follow them home that night and cause mayhem.

Like Michael Myers these psychopaths struck on Halloween night (which is not totally unsurprising as this film was somewhat of a homage to that style of story-telling).