Overcrow

Description
The overcrow looks like a mundane crow wearing a small, red hat. Of course, it is much more than just an ordinary black bird. The overcrow possesses such a strong sense of self-awareness that any creature that comes within 100 feet of it begins to believe that it, too, is a crow.

One may wonder, "Where did overcrows come from?" The last scholar who asked this brave question returned from a 10-year quest gibbering like a loon. All he could say was "CHAR-LO-MAIN!" Once his madness was cured, the scholar had no memory of the "char-lo-main" or the origins of overcrows. Some knowledge is best left unsought.

Clever mages employ overcrows as traps in dungeons. As adventurers are distracted by their need to "caw!" and flap their wings, the dungeon's inhabitants rob the adventurers and leave them defenseless against the other dangers of the dungeon.

Appendix

 * 1) https://www.patreon.com/posts/366-days-of-day-33326005