Sharptooth

Sharptooth is the main antagonist in The Land Before Time. He is a massive Tyrannosaurus rex who is blind in one eye due to an encounter with Littlefoot and Cera, leading him to develop a hatred against them. He is voiced by Frank Welker.

Personality
"Although one of his eyes were swollen shut, he was growling softly, enjoying his moment of revenge."

If you read the Land before Time book that was sold along with the movie, you will find out more about his personality. Sharptooth seems the vain to the extent that where he feels that his looks should go unscathed and if so happen they do, he becomes very angry about this.

Role in the film
Sharptooth first appears wondering through a swamp while a Littlefoot and Cera are playing. The sight of Sharptooth causes the two young dinosaurs to flee into a thicket, where Sharptooth attempts to attack them. As Sharptooth nears Littlefoot, a thorn strikes Sharptooth in the eye, blinding him in that eye. Enraged at his injury, Sharptooth emerges from the thicket and corers Littlefoot and Cera. Before he can attack them, Littlefoot's mother intervenes and defends the two. Sharptooth immediately turns against her and the two battle across the landscape.

Though Sharptooth injures Littlefoot's Mother by ripping a large chunk of flesh from her, she manages to gain the upper hand and knocks him down. The battle is interrupted by an earthquake, during which Sharptooth turns his attention to Littlefoot and Cera. As he attempts to kill them, Littlefoot's Mother comes to their rescue and knocks Sharptooth into a chasm. However, she dies soon afterwards.

Some time later, Cera enters the chasm and finds an unconscious Sharptooth. Presuming him dead, Cera begins to ram into him repeatedly for fun. However, this causes Sharptooth to awaken, terrifying Cera. Before Sharptooth can attack, Cera escapes the chasm. Sharptooth eventually manages to escape the chasm as well, but Littlefoot refuses to believe that he is still alive.

Sharptooth later attacks the group, which has been joined by Ducky, Petrie and Spike, and pursues them through the terrain. Eventually, the group escapes by fleeing into a small chunk in a large wall which Sharptooth cannot enter. In spite of this, Sharptooth continues towards the Great Valley, where the other dinosaurs are travelling to. As he begins to near the Great Valley, the group notices him and formulates a plan to kill him.

Ducky lures Sharptooth out of a cave and towards a lake, where the rest of the group attempts to knock a boulder onto Sharptooth, which will cause him to fall into the lake and drown. Sharptooth endangers Ducky, forcing Petrie to intervene. However, Sharptooth jumps onto the cliff and attempts to kill the rest of the group. However, Cera returns to help the group and rams into the boulder, causing Sharptooth and the boulder to plummet from the cliff. As Sharptooth falls, he grabs onto Petrie, dragging him into the lake with him. However, the force of the boulder knocks Sharptooth unconscious, forcing him to release Petrie, who escapes the lake safely. Sharptooth then sinks into the lake and drowns.