Therizinosaurus

Of all animals that ever lived on earth, the Therizinosaurus probably had the longest claws. 

Of all animals that ever lived on earth, the Therizinosaurus probably had the longest claws. It used them to dig, grasp, pierce, and peel off bark. It lived towards the end of the dinosaur age, together with other herbivores such as the Kentrosaurus and Pentaceratops.