I Need Some Help (Prank Wars) - Comments

Stick eggs inside their engine bays on their car, when it heats up it'll smell of eggs xD

Oh yea...if you really wanted to kick it up a level, you can also glitter confetti them; just put glitter in the vents in place of baby powder. POOF.

Ohhh....you know what is surprisingly really hard to fix but it won't cost you money? (just your time and determination, I guess...)

One time, my youngest sister and I pulled a prank on our other sister where we nuggeted every single bag and backpack she owned...for some reason she has a lot.
This wasn't me, but my youngest sister (the same partner in crime) short-sheeted her three nights in a row.

If it has to be something with a car, it's really funny to pack the inside of the car to the brim with packing peanuts...it's kind of a pain to clean up because you can't seem to get all of them but it doesn't harm the car.
Others that come to mind...corn starch/baby powder in their air vent? UGH...messy...seen it happen with a hairdryer.

Well, that's all the ones I can think of...sorry, I don't think I was much help. Good luck to you in your prank wars!

cover their cars in post it notes?
saran wrap the car, or the toilet.

fill the backseat with unbuttered popped popcorn.
buy a magnet bumper sticker (that way he can remove it) that says something weird-funny-crazy and put it on the bumper and see how long it takes him to realize it's there. Something like I speed because I have to poop' or something goofy like that. good luck!

double post, sorry