<human>: Give me a shortened version of the text

I live in a house at my school owned by the college. I leave a keruig machine out in our kitchen for everyone in my house to use, as long as they ask permission. I also supply the accompanying k-cups. 

I've noticed (along with other housemates) that a girl who definitely does not live in our house has been coming in and using the keruig (and the cups) on a pretty much daily basis. Of course, she hasn't asked my permission, nor do I even know who she is.

So I've decided to play a prank on her to teach her a lesson not to use things that obviously aren't hers. 

Any suggestions reddit? I'll film it and post it here if you can help me out.
<bot>: Girl who I don't know using my keruig w/o permission. Want to teach her a lesson via prank.