Is there a name for this specific concept? Where somebody invents something (to do them good) but then that thing turns around and backfires on them?
I really hope there’s a single word for it out there… more convenient yanno.
There’s probably a German word for the concept that there is a German word for everything.
Indeed - for OP’s purposes, I came up with this (but I don’t speak German, so it may make no sense at all): Erfindungselbstfehlzündung
Google seems to like it well enough!
Or better, Erfindungdererfinderselbstfehlzündung: