xkcd #3100: Alert Sound
Title text:
With a good battery, the device can easily last for 5 or 10 years, although the walls probably won't.
Transcript:
[A loud sound appears out of nowhere in the upper left part of the panel, around the word are many small lines going away from it and before the word there is a warning emoji. In the lower right corner Cueball is sitting in an office chair at his desk in front of his computer. He is holding his hands to his head and begins by shouting and then talking.]
⚠ Boop!
Cueball: Aaaaa!
Cueball: I heard it again!
Cueball: Where is that coming from!?
[Caption below the panel:]
It turns out living well is only the second best revenge. The best revenge is making a tiny hole in someone's wall and dropping in a battery-powered capsule that, every 6-12 hours, plays the alert sound of a USB device connecting.
Source: https://xkcd.com/3100/
explainxkcd for #3100
ThinkGeek used to have the annoyatron that would do that. https://www.youtube.com/watch?v=5z1I1grocF0
God I miss the OG ThinkGeek so much.
I got so much mileage out of my annoy-o-tron and the second version that had a few "spooky" sounds added as options. The fact that it had a magnet on the back made it so easy to hide in an office because it could stick to the backs of so many things. The most successful were the backs of (or bottom of if on wheels) filing cabinets,