The Butt Set
Remember when you would see the phone guy in your neighborhood, and he had that weird phone on his toolbelt (see image)? That was the only cool, different-looking phone you ever actually saw.
I know there were all sorts of other designs, but a typical kid never saw them in the real world. Most phones were the same, and everyone had that same set at their house. Sure, occasionally it was tinted green, but it was the same phone. Eventually, my parents had a baby blue version of the phone in their bedroom. I used this fact to astonish my friends, as they had never seen such a thing. They thought I was making it up.
Of course there were futuristic designer phones in movies and on TV. But except for sci-fi flicks and shows about rich people, the only really different looking phone you ever saw was on the belt of the phone guy.
Well, it turns out that phone is called a "Butt Set". You heard me. "Butt set". I am not making that up.
The pranking practically writes itself. I can imagine a series of conversation between dispatchers and kids pretending to be phone guys: Requests for replacements for unsightly misshapen butt sets, orders for interns to bring left-handed butt sets, or complaints that when the phone guy showed up, his butt set had a visible crack in it.
I could probably easily find out more info to tell you about the butt set, but there is no way I'm going to Google a term like "Butt Set". You're on your own folks.
Happy new year.