Terrorsaur is one of the Predacons who work for Megatron and one of main antagonists in season 1 of Beast Wars. He was one of the original six Predacons who stole the Golden Disk. His beast form is a pterodactyl. In his deluional mind he believes he can lead Predacons better than Megatron and attempt to coerce others for support: other Predacons rarely ever listen. He is often teamed up with Waspinator, and later with Inferno as well.
Terrorsaur is voiced by Doug Parker.
Terrorsaur often tried to take over as leader of the Predacons, blowing Megatron to bits at one point, but Scorponok repaired him.
Also during a particular fight against Maximal, when Megatron purposely 'relinquished' his command of Predacons to Terrorsaur, he not only allowed Maximals to invade the Darksyde, Black Arachnia went MIA and Maximals left with the Darksyde rigged and had many of information hacked, effectively proving Terrorsaur's unfitness for a leadership (a point Megatron is not afraid to bring out). Megatron then asked other Predacons if anyone still believes Terrorsaur can lead and wishes to follow him. Nobody dare uttered a whisper.
When Megatron turned Rhinox into a Predacon, his aggression caused him to attack Scorponok and Waspinator. Terrorsaur was interested in joining up with him and overthrowing Megatron, but Rhinox was uninterested in working with him. This caused a fight to break out between Terrorsaur and Scorponok when Megatron sent them after Rhinox.
After more than few attempts to usurp Megatron and failing in all such attempts, realizing his own incompetence in the process, Terrorsaur eventually became more obedient soldier.
In Episode 27, "Aftermath", the premier of Season 2, Terrorsaur was killed along with Scorponok when the quantum surge caused them to collide on their hover platforms and fall into the lava pit. However, a comic (non-canon) reveals that he survives and becomes a transmetal.