Crash! Bang! Bang!
When your victim is using a stall in a public restroom. Walk inside the restroom and start throwing rocks at the ceiling. All he can see is dust forming while listening to banging and crashing noises.

Open Public Urinal Prank
some public restroom's have open urinals that do not have divider walls installed. As soon as you see someone starting their piss session, walk over to him, point at his midsection and start laughing. This will piss him off for sure! But he cannot do anything until he is done pissing. This give you plenty of time to run the heck out of there.

Restroom Disco
When no one else is inside a public restroom install a disco ball on the ceiling. Most people will never notice it if you put it high enough. Then when someone goes to use the toilet. Turn off the lights and turn on the disco ball.

Lights Out
After someone has gone into a public restroom and sat down on the toilet in a stall, turn off all the lights and walk out of there.

Gas Station Restroom
Write the following on the restroom stall wall: Big Bubba is coming to kick your ass on: (insert today's date here) after sundown. Then whoever uses the stall after you that night will see today's date and hurry and flush before Big Bubba shows up.

Hey! How is it going?
When you notice there is someone taking a crap on the toilet in a public restroom go into the stall next to him. Then slip a newspaper underneath and tell him to take a look at an article. Choose an interesting article and stir up a conversation. Most people will hate that. People just wanna do their business get in and out and thats it.

Revenge On Plumbers Crack
What could be more disgusting than a plumber's butt crack when he bends over to repair your toilet or sink? nothing! and it happens every time. So its time for revenge. Next time your plumber shows crack, drop a few conis inside there. He may hit his head on a pipe upon feeling those pesky cold coins slithering down his ass. Not only that, he will be angry. So just tell him its for his kid's college fund. That should clear everything up.

Under The Stall Tug
Wait until your victim goes into a public restroom stall. As soon as he sits on toilet and starts his business, go underneath the stall and start tugging on his pants. If you can try to take his shoes off.

Bathroom Pudding
Smear chocolate pudding all over a bathroom. Works best in public bathroom, as people will most likely not clean it up. They will just try to avoid it but at the same time think its poo.

Restroom Dollar Bill Gag
Before urinating in a public restroom urinal, clog the drain. Then pee, after you have filled the urinal with piss drop a crumpled up dollar bill in there. Make sure it gets soaked with urine. Then hangout in the restroom and see which poor sicko tries to take it out and clean it off.