When a character dresses up in a costume that distinctly resembles a known type of animal. In most cases it is a full-body costume, but there are exceptions.
Also note that this does not include characters simply wearing an animal hat.
The following tags implicate this tag: reindeer_costume, boar_costume, fox_costume, frog_costume, cat_costume, cow_costume, tiger_costume, panda_costume, bear_costume, penguin_costume, dog_costume, bunny_costume, mouse_costume, lion_costume, wolf_costume, tanuki_costume, monkey_costume, seal_costume, sheep_costume, dragon_costume, and horse_costume (learn more).