Long neck dinosaur-Therizinosaurus!
Therizinosaurus ("scythe lizard", from Ancient Greek "therizo", meaning "to reap" or "cut off", and "sauros", meaning "lizard") lived in the Late Cretaceous Period, about 70 million years ago. It was one of the last and largest representatives of its unique group, the Therizinosauria. Its fossils were first discovered in Mongolia, and were originally thought to belong to a turtle-like reptile. So far only a few fossilized bones of this prehistoric animal have been found, including the eponymous claws. However, inferences as to their physical traits could be made based on the other known members of their family.
Therizinosauria had small skulls atop long necks, with bipedal gaits and heavy, deep, broad bodies. Their forelimbs have have reached lengths of up to 2.5 m or even 3.5 m in the largest specimen. Their overall estimated size was 10 m in length, and five tons in weight. Their most distinctive feature was the presence of gigantic claws on each of the three digits of the front limbs. The claws probably reached just under one meter in length, and are the longest known from any animal on Earth.
Theirs feeding habits are not known, since no skull material has been found to indicate their diet. However, like other therizinosauria, they were most probably herbivorous.