Some number of years ago I saw a huge traffic spike on https://jsonip.com. After investigating, I saw that someone who seemed to have a misconfigured squid proxy that wasn’t valid IP data was hitting the api hundreds of times a minute.
The scale of jsonip was a lot smaller back then and still just a personal project but the requests were significantly crushing the server in addition to regular traffic.
As a mild joke, I updated the code to return “418 You are a teapot” for the squid proxy briefly. Just long enough for the user to be “wth” and investigate so they’d update their configuration. I just targeted the obviously malformed requests.
Within a day or so the proxy either stopped making requests or got fixed.
I got a laugh out of it and removed that code. Hopefully the person on the other end also got the joke.