Put on a big white dress. Maybe a veil if you haven't shaved.

You need a big crane that lifts a huuge concrete plate high enough with a remote release of said plate. Then move the crane accordingly so the plate will drop at high speed onto the wedding cake and make it splash.

Pretend you know everyone?

Say you're FBI.

You go to a Mexican one. Nobody really cares. They’ll feed you, give you plenty to drink, and make sure you dance.

Despite the name, the move is not to make a scene, don't wander around looking lost, act like you belong, grab some punch, talk to people and so forth