Lice
Open a box of lice powder and just leave it on the bathroom counter. People using the bathroom will scratch their heads wondering who is the one with the lice in their hair.

Poo In The Urinal
Drop a pile of real poo or fake poo (a baby ruth candy works well) inside of a urinal.

Wipe Your Butt On The Guest Towel
Ever been the 'guest' somewhere but didn't feel like you wre being treated like one? Well, here is what you can do to get back at them. Use the 'guest' towel to wipe your butt with, instead of the toilet paper.

Clean
Restaurants and hotels usually have a checklist in their restrooms that employees can check off whoever cleaned it last. This is to know who did it last and how long its been since the last cleaning. If you have a pen handy you can just mark it clean yourself, even if it is messy, smelly, needs toilet paper and has a wet floor. You can also put the same initials for the last cleaning as the current cleaning...if the management cares, then JR will be lectured about doing a half-ass cleaning job.

Where is the showerhead?
Go in your victim's bathroom and remove the showerhead from the shower.

Greasy Toilet
Grease the bathroom toilet seat with something like neosporin or vaseline. The more clear the substance is, the more difficult it is to detect before the victim sits on the seat.

Soap In The Showerhead
Unscrew the showerhead, place small pieces of bar soap inside, screw the head back on. Be sure to use some teflon tape so it doesn't leak. When you victim goes to take a shower, he will be treated with a shower of bubbles.

Bathroom Thunder Storm
As soon as your victim sits down to do his business in a public stall, go into the stall next to his.Then flash a light underneath the stall and yell, "Lightening!. Wait a few seconds, then bang on the stall wall and yell, "Thunder!. Then a few seconds after that, yell "RAIN!" while flinging a bucket of water over the stall. This may piss of your victim so i suggest running like hell.

Toilet Jello Water
Stir several boxes of jello mix inside the toilet bowl overnight. When your victim goes to use the toilet in the morning, he or she will see a solid jiggly jello in the bowl.

Bathroom Sensor
Take some black duck tape and tape over sensors in public bathrooms so toilets can't flush and sink water never turns off.