Burn their car to the ground, make it look like an accident, then stand helplessly nearby with a hose and a sympathetic look. It may be extreme but oh well.
Speaking of cars you could also wrap their cars in plastic wrap.
Cover their room in post it notes.
Give them a kitten that loves to nap on keyboards.
After a large dinner of chili con carne and taco bell get rid of their toilet paper and put an empty roll on the tp holder and write "ha" on it. I guess you could say they will have a *puts on sunglasses* ****** time.
Replace all of their tasty Starburst flavors with lemon.
Contract a really bad cold, then sneeze on them.
Book them a flight next to a toddler with sensitive ears.
Fill their sink with hair from an undisclosed location.
Buy them generic brand cereal instead of the real deal.
Knee 'em in the nads then sock 'em in the face. SUCK IT LOSER!
Shoot their legs with a shotgun!!!
put skunks in thier locker and leave a note in it
Shove them into a vase
Leave a life-sized zombie cardboard cutout in their locker for them to find, w/a motion activated tape player w/loud attacking zombie sounds on it.
If all else fails, make them a fruit plate that only consists of cantaloupe and honeydew.
that's all for now let me know if you want more but I will only make one more of these.
Thanks swagmasters of ultra swags who shop at snapbacks are us