Therizinosaurus was an herbivorous theropod from late Cretaceous Mongolia. It had very long, sharp claws, though the purpose of the claws are unknown.
In Zoo Tycoon 2Therizinosaurus was never made an official animal by Blue Fang, though fans of the series have made various renditions of the creature.
Cretaceous Calamity was originally set to feature a Therizinosaurus, its model based off of the base game Tyrannosaurus rex. Due to a fairly recent reboot of the project, it is unknown whether or not the dinosaur will see an appearance in the UXP.