The owlbear is one of D&D’s signature monsters, created by Gary Gygax. It first entered the game in the 1975 first supplement "Greyhawk" and was depicted in the 1977 Monster Manual as a cross between an owl and a bear.
Its unlikely real-world origin was a Hong Kong–made plastic toy that Gygax bought to use as a tabletop miniature. That very absurdity made it beloved, and it has appeared in virtually every edition of D&D since.