Crazy Plot Device Week

Hi! I thought we could start a thread to discuss our Crazy Plot Devices this week (and the rest of this month!). I'll go first...

My two protagonists, lowly high school sophomores, have just realized that they accidentally made a serial killer go after them. Not so crazy, because my novel is all about demon possession, but still.

I am going to have my protagonist invite her nemesis for a drink.

Mysterious figure in the woods who threatens the party of travelers for disturbing the peace of the wood is actually FMC's sister.