When i was in 4th grade , i put mustard in one of my friend's burger because he had told me that he hated mustard. turns out he was actually allergic. he didnt come to school or 3 days and i was scared that i k*lled him. to this date noone knows that i did it.

edit: wow so many upvotes that's cool. i would like to say that don't worry we r still on pretty good terms.