Reproduction
Chat message "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA". That's it.

Doing this too many times crashes the server, but usually just times you out. This doesn't happen server side however, so this can lead to some quirky side effects.

According to my buddy Lolt every time this happens one core crashes. When the server runs out of cores, the entire server crashes. Sending the chat message then reconnecting on a 6 core server crashed on the 6th attempt.