Share things that you've discovered that might be able to be used offensively. I'll start.
>AUX earbuds conduct electricity extremely well, leaving a horrible cracking sound in the ears of the user in many cases. (Wouldn't do much more than static though unless you want to really fuck them up)
>Toothpaste (Colegate), coke and hydrogen peroxide make a massive fuck you mess. It's about 2 bottles of coke, 1.5 tubes, and 1/4 - 1/3 of a cup. Useful for ruining someone's day that fucked with you, especially since it can be done under doors in areas without cameras.
>Buy crickets online. Release under doors.
>Plastic wrap over a toilet seat. Lay carefully so your trap is not immediately revealed by creases.
>Restaurant ketchup packets under toilet seat.
>Adding table salt to an impure mixture of isopropyl alcohol will allow you to easily separate out the alcohol from the water. Useful for getting a more potent antiseptic, industrial cleaning, or any other fun uses you can come up with for something that burns and is cheap.
>Find a tranny's info. Bait 'her' into a 'relationship' for a few weeks. Once you've sold him, tell 'her' that it isn't working out. Repeat with other friends, or just use fake accounts and numbers to lead em' on. Wait for the inevitable.