Shantak-kun, a female Shantak originating from the Cthulhu Mythos, features a bird-like body with a horse's head and bat-like wings. She acts as both pet and companion to Nyaruko, a primary agent of the Space Defense Agency. Her core ability involves versatile transformations, shifting size from as small as a rabbit or dog to as large as a multi-story building. She morphs into various vehicles, most notably the spaceship that transported Nyaruko to Earth, adapting to situational needs like transportation or combat support. Shantaks biologically produce eggs regarded as a precious and expensive space delicacy, though Mahiro Yasaka consistently rejects consuming them despite Nyaruko's endorsements. Throughout official media, including light novels, anime seasons, and OVAs, her role remains consistently supportive through utility-based transformations, without elaborated personal storylines or character growth. She does not appear in the OVA "Haiyore! Nyaruko-san F".