It is called
Coulrophobia.
I am so freaked out by clowns, I can't even take my nephews and nieces to the circus. About fifteen years ago, some freak in a clown suit thought he would help me with my fear and kept trying to strike up a conversation with me, even after I warned him twice that, "No offense, I find clowns creepy, you are making me uncomfortable, please walk away."
He didn't listen.
The guy walked up and put his hand on my shoulder and tried to debate me about this, and my fight/flight response kicked in and I slammed him to the ground and had grabbed a shovel that was nearby and went to open his head with the business end before two guys knocked me down and took the shovel away--it took two more people to restrain me as I was crazed with fear.
I had no memory of it--just snapped and went berserk. The fear is real and powerful. Now I pretty much avoid being anywhere near an event where a clown may be present--including birthdays--I have to walk the other way when I see them.