SUBREDDIT: r/AskReddit
TITLE: How does one exact their revenge?
POST: My friend's phone was stolen and a new phone number appeared in his Lookout app. When it first happened the phone number didn't work and he couldn't trace it without paying money on a reverse phone search. Lookout still can't locate the phone physically. I think the phone is gone for good, but may have the person's phone number. It's been 2 years and the phone number works again. No one answers and it goes to a vm saying you reached that number and not a person's name. What are some good ways to prank someone using just their phone number?
TL;DR: 
If you have a deserving person's phone number, what is the worst/best way to exact revenge?! What are some good pranks reddit has heard of?