A great prank phone call is a work of almost sublime art. First of all, it's a fairly aggressive act and one that relies entirely on the recipient's imagination. A great prank phone caller has to be willing to insult, to badger, to bully, and to cajole all without tripping into the territory of actual injury. A great prank caller creates an elaborate reality alternative to our own, then draws the recipient into that reality.
When you're talking on the phone, you're at the mercy of whomever is on the other end. You can't see them, and they can't see you, so there's a basic disconnect going on that requires intense collaboration to bridge. Put simply: You both have to agree that you are talking to the other person and that the person is who they say they are. That's true of customer service representatives and true of your family. If someone who sounded exactly like your mother picked up her phone and started talking to you, you would just assume that you were talking to your mother.
So that's why it's so magical to find a truly great pranker. The best prank caller in the world is, of course, Longmont Potion Castle. His calls are weird, and don't go to the typical place of insults and mean humor. He collaborates with his recipients to take them and the listener to a truly strange audio collage that kind of breaks your brain if you try to explain it to somebody that doesn't know about it. Like, he'll call several different Radio Shacks all at once and have the associates all talking to each other. In a way, his calls become about themselves. He'll also call celebrities. When it comes right down to it, he'll insult people. Here's an interview with him.
Anyways, there's a Twitter hashtag that is, like, what if millennials were making prank calls. Pretty hilarious, we know. Here's a sampling.