Graboid
Background
Graboids are Pre-Cambrian, underground dwelling large worms. They hunt by detecting the vibrations of nearby prey. After maturing they produce three Shriekers.
During the events of Tremors (1990)
A Graboid kills Edgar's donkey Justine and then chases him up a transmission tower where it stays until he dies. As Rhonda LeBeck is packing up for the day, a Graboid follows her and nearly gets her before she gets into her truck and drives away. As Carmine - Roadworker is breaking up the road with a jackhammer, it impales into a Graboid which screams and quickly moves away, dragging Carmine with it and eventually pulling him underground. When Valentine McKee and Earl Bassett are trying to leave town, a Graboid tongue grabs their truck, but they manage to get away. As Jim - The Doctor and Megan - The Doctor's Wife are finishing up working on their house for the night, their generator disappears. Jim starts to pull on the chord stuck in the ground and is then grabbed and killed by a Graboid. Megan runs to their car and the car is pulled underground along with Megan. A Graboid pops out of the ground and starts to chase Earl and Valentine. They jump across a cement canal and the Graboid kills itself by ramming into the concrete. As they and Rhonda are walking towards Rhonda's truck, they are chased by another Graboid and climb onto a large boulder. They try and wait out the Graboid, but it is waiting for them when they check to see if it is still there. Rhonda realizes the Graboids can sense seismic vibrations and they end up sleeping on the boulder overnight. Rhonda comes up with the idea to use a long stick to pole vault to her truck after they find the Graboid still waiting for them. They get into Rhonda's truck and drive back into town and tell the others about the Graboids.
In Perfection, a Graboid emerges from the ground and everyone runs into Walter Chang's store except Nestor and Melvin Plug. They hear Mindy jumping on her pogo stick and Valentine grabs her shortly before Nancy runs to her. A Graboid grabs the pogo stick and Nancy and Mindy runs into their house while Valentine jumps onto a truck. Another Graboid comes and Rhonda gets stuck in barbed wire while she is trying to run away. The Graboid starts to pull Rhonda towards it and Valentine helps her. A Graboid bursts into the store and drags Walter underground. The other Graboid breaks into the store and Earl, Valentine and Miguel climb to the roof while Rhonda climbs up a water tower. A Graboid bursts its way into Burt Gummer and Heather Gummer's basement. They manage to kill it with an elephant rifle. The Graboid that originally attacked Valentine and Earl's truck starts to attack different buildings to test their structural integrity. It pushes over Nestor's trailer and pulls him underground. A Graboid then grabs it and destroys Burt and Heather's truck. After a lawnmower they were chasing falls over, the Graboids race towards Valentine who is running towards a bulldozer. Rhonda yells to Valentine to stop and breaks a pipe leading to the water tower, which attracts the Graboids. Valentine runs to the bulldozer and attaches the trailer to it and picks up the others. They drive towards the mountains, but before they can reach them, the Graboids set a trap and dig a pit in the direction the bulldozer is heading, causing it to crash. Burt uses a pipe bomb to make the Graboids run away, but they come back again. They use another one to make them run away while they run towards a set of boulders. They manage to kill one by feeding it a pipe bomb, but as they try it against the last one, it spits the pipe bomb back at them. Valentine, Earl and Rhonda are forced to run off the boulder and as they try to run back, the Graboid emerges in front of them. Valentine has the idea to use himself as bait and runs towards the edge of a mesa. Earl runs after him followed by Rhonda who hands Valentine a lighter to light the fuse on the last bomb. Valentine uses the bomb to make the Graboid run towards the edge of the mesa and it falls to its death.
During the events of Tremors 2: Aftershocks (1996)
In Chiapas, Mexico, a Graboid hunts and kills an Oil Worker. Later, a Graboid starts to follow Earl and Grady Hoover in their truck and they use a remote controlled truck to bait the Graboid into swallowing the toy and a bundle of dynamite. Earl then blows up the Graboid. They then continue to blow up Graboids one after another. While eating lunch on a large rock, a Graboid takes their radio which Grady had left on the ground. During the night a coyote howls until it is eaten by a Graboid. The next day,a Graboid grabs the chains they were using to attract the Graboids and starts pulling the truck until it crashes it into a rock, ripping the chain off the truck. Grady notices a Graboid is heading away from their direction and he and Earl follow it. They are ambushed by the Graboid and Earl reverses his truck down a slope. They walk over towards the Graboid who appears to be distressed. During the night, the Graboid shrieks in pain and when Earl and Grady check on it, they find it ripped apart from the inside. The other Graboids in the valley also start to shriek and birth Shriekers.