An artistic error or mistake, usually in the anatomy, but it can be in other elements such as composition or perspective, or other errors such as wrong eye color for characters, etc. If the anatomical error is minor, this should be used instead of bad anatomy.
With ai-generated artwork, it isn't uncommon for most images to have one or multiple mistakes.
The following tags implicate this tag: bad_anatomy, bad_arm, bad_feet, bad_hands, bad_horizon, bad_leg, bad_reflection, wrong_feet, and wrong_hand (learn more).