A few fun fallbacks.
I have engaged in the usual bits of nastiness over the past decades. A few favorite examples are listed below.

Nitrogen tri-iodide is a fun substance to mix up in a high school chemistry lab: stable when wet, once it has dried it will go off if a fly lands on it. When some punk decided to start stealing valuables out of lockers I baited mine with some tempting sacrificial items painted with the stuff, then carefully remembered not to use my locker for anything afterwards. It took just two days for the locker thief to make a move: even if we had not heard the bang, his surprised shout brought scores of students and teachers into the hallway to reveal his guilt. The iodine stains were deep in his skin and took months to disappear.

Do not make it a habit to piss off people who work in computer labs for they will create toner bombs and cover your domicile in a fine dusting of the nasty black powder. A simple diaphragm container slipped under the door, then stepped/jumped on, will eject a fine cloud of printer toner all over the immediate vicinity. If carpet is present, the damage immediately jumps to replacement level.

On several occasions I have engaged in the quick and dirty lock cylinder attack: obtain a key blank to match the lock you want to damage, smear said key in slow drying/gap filling superglue, then insert the key into the lock and with a savage twist of some handy pliers, snap off the end.

Before Tyron cranked down their IR remote control booster's power output, it had an effective range of a hundred yards with a fresh 9V battery in the case. Use with binoculars or small spotting scope and a programmable remote control. Once you lock in your victim's TV/VCR/cable box type and have a steady aim, you can change channels at will or simply turn off the device at random intervals. Lots of fun on college campuses on nights when you and your friends are bored and too lazy to leave the dormitory blocks.
( Felis Concolor, Fri 6 May 2005, 9:38, Reply)