You have a birthday party when you're six. Your parents hire Bobo the Clown to entertain: magic, face paint, balloon monkeys, that sort of stuff. On the way to your party, a friend's parent hears on the radio that Bobo the Clown is a murderous pedophile wanted for the armed chainsaw robbery of a local Kids "R" Us. As the children without chaperones huddle in your mom's dark closet and take turns sobbing into her blouses, your dad tries desperately to catch Bobo on his cell to cancel the appearace.
Somehow, Bobo never shows up. Everyone breathes a sign of relief, your guests go home with Ninja Turtle kazoos and slices of Seran-wrapped confetti cake, and you hope that these parting gifts are enough penance for their abject terror. So concludes the third-worst birthday you'll ever have.
As it turns out, Bobo the Clown was on his way to your party when he was struck bodily by a decommissioned city bus and ran himself through with his own chainsaw on impact. A fortunate coincidence saved your sixth birthday party and the lives of you and your parents.
...Or did it?
You grow up to become a robust reader of random wikis and one day you find yourself having traveled through time to the exact date of your sixth birthday. While buying a pair of Bugle Boy suspenders to blend in with your surrondings, the Kids "R" Us recieving your patronage is heldup by a murderous, chainsaw-weilding clown.
That's when you realize: YOU must murder Bobo the Clown. If you leave it to chance and it wasn't someone else who happened over the clown with a city bus, Bobo will show up at your birthday party, chop up your parents, and feed them to you while your friends watch. By now you can surely connect the paradoxical dots: If you're murdered at six, you can't grow up, can't become a robust reader of random wikis, can never time travel through time, and certainly can never stop that evil clown.
This time you were fortunate. You were wise enough to recognize that Bobo had to die at your hand and, incidentally, that you had always wanted to steal a bus. But that clown nearly had to step on your right big toe for you to come to the realization, like Danzel Washington in the time traveling film Deja Vu, who is repeatedly assualted with clues of his own time travel and fails to make the connection, you won't always be so lucky.