Nyaruko's pet. A female shantak (monster in Cthulhu mythos, a bird with horse's head and bat's wing). have many different forms including enlarging to stories high, a dog's size. or turn into different vehicles. According to Nyaruko, shantaks' eggs are precious and expensive food in space, despite Mahiro never accepts to eat them. Nyaruko arrived on earth by taking spaceship transformed from Shantak-kun.
(Wikipedia)