What is a good prank?

I am planning on having a prank competition with my friend. I don't want to do anything, like to hurt him, just something to like, disgust him. I wanna put something in his food. Again, not to hurt him, just disgusting him. Since he knows we are having a prank contest, he won't be as mad. What should I put in his food?

You could kiss his crush or sister or worse post on a website that he goes to (I.e. facebook,twitter, ect) and so you are thowing a surprise party for him at his house but when he gets home there will be nothing

Here is the best prank videos for prank lovers.
Todd & Day pulls an epic seizure prank on their friends as a birthday gift.
https://youtu.be/f4oier73j_s

Good Pranks are tried and tested hoaxes, practical jokes and tricks that have been played on friends and family alike! ... The Top 10 Good Pranks in All Categories! ... KIDS if you want to play good pranks, get an adult with sound judgment involved, don't get into trouble and don't be