Some of my favourites:
It is an error, which disappears or alters when it is attempted to be identified by analogy to Heisenberg uncertainty principle in quantum physics.
Reality 101 failure
The program (or more likely feature of a program) does exactly what was asked for, but when it’s deployed it turns out that the problem was misunderstood and the program is basically useless.
This is a prototype that ends up in production.
MEGA MOnolithic meTHod. Usually, it stretches over two screens in height and often contained inside aGod Object (an object that knows or does too much). Megamoths of greater size than 2k LOC have been sighted. Beware of the megamoth!