Put a timer on an airhorn switch or something, and hide it in a library.
Offer someone a candy apple, but it's a red onion dipped in caramel.
Host a "costume awards ceremony" in a park, give the award to someone who "Looks almost like a real live Nazi!"
Create a tinder with my friends, ask someone to "Give me $5 and see what happens". Apparently that's a meme?
If someone actually sends the money, give them the link to a video of the girl who took the pictures (fake) killing herself or dying in a gruesome way.