Doku-Koala is a familiar summoned by the witch Viola in the anime The Family Circumstances of the Irregular Witch. This creature serves as the second familiar called forth by Viola, who sought a companion with methods of attack that went beyond the use of poisonous plants. True to its name, Doku-Koala carries a variety of different poisons.

Despite possessing a rather rough personality, the creature functions as a mascot-like presence within the story. Alyssa, Viola's adoptive mother, affectionately refers to this familiar by the nickname Ee-chan. In terms of notable experiences, one incident involved Ee-chan gathering materials in snowy mountains, eager to find useful items and earn praise from Viola. During this outing, an unexpected turn of events led to a young yeti mistaking the familiar for a baby of its own kind, resulting in Ee-chan being captured.