Help me find this film?

So i have no idea when this came out, all i know is that i saw it when i was much younger (im 21 now) it was about a clown who was hired for a childrens party, at the party one of the children thaught it would be funny to tie the clowns shoelaces togeather. This ended up in the clown stumbling back onto an open dishwasher, where a knife was placed, ready to be cleaned. The clown died. I remember a scene in a graveyard with a bunch of clowns all coming togeather. Basically the dead clown comes back to life and torments the now grown up child. There is a graphic scene set in a classroom where the boys penis/testicles are torn off by the clown. If you have any ideas please let me know x