What are the most nastiest pranks you've done to a person? [family,friends,schoolmates,etc..]

oh ehe...i know this is really cliche, but just because it was funny, i put shaving cream on the toilet seat. i just heard the girl scream. so funny...

and another time, i put ketchup, honey, hot sauce and mustard all at once on the underside of all the railings in my school. it was hilarious! people were stopping and fighting and screaming and ahh...so funny.

That's hilarious! I had my friends convinced that the pictures of my cousins on my desk were really my kids for the entire day, I had a really detailed story about them living with their dad because I was only 14 when I had them, and how he was in prison so they lived with his mom, and it was just hilarious.

I had a very terible day because i had 3 exam for a scholarship and an interview .After that i am so tired so i slept all day ^^

mine was a group prank we convinced several people that a girl we all knew was pregnant
and i managed to convince my mother that i went to spain