The Ankylosaur Monster is one of the Corrupted Gems that appears at the three-part finale of My Little Universe: Season 6.
Appearance
It is a large, four-legged behemoth with brown skin, cloven hooves, a parrot-like beak, and crystalline armor from its back down to its head, making it armed like a tank.
History
It appears only briefly during the Season 6 finale: as the Harmony Gems were escaping the White Diamond Space Station, it escaped and manages to find them just before they could enter the Sun Incinerator. It rams into the ship, sending it out into space.
It's fate from here is entirely unknown.