My best friend has been out of town for the last few weeks, and won't be back for another few. The last time I went out of town for an extended period of time, I came back to giant sparkly foam letters on my door spelling my initials and pink glitter in my mailbox. We live in the same apartment building.
What can I do to his door/mailbox before he gets back? (Like kinds of things can I shove under/in them)