Buster is a crash test dummy that plays an important role in many experiments by taking the place of a human subject in the more dangerous myth tests. The first and most recognized of the dummies used in the show, Buster was introduced in the beginning of the first season for the Exploding Toilet Myth. Adam had purchased the dummy to take the place of Jamie (who had second thoughts about testing the myth because he realized the foam he would be using was flammable), and Jamie gave it its name.
Because of the nature of the situations in which the MythBusters use him, Buster has been subjected to forces and situations that far exceed his original design parameters as an automobile crash test dummy. As a testament to the danger of the tests in which he is used—often resulting in his being broken into pieces, burnt, or otherwise mutilated—Buster has had to be extensively repaired and rebuilt over the course of the series to the point that an entire special was devoted to his being completely redesigned and rebuilt as "Buster 2.0". Buster was designed with quick and simple repair in mind, and boasts improved joints, with a more realistic range of movement, and easily replaceable poplar wood "bones". Poplar was chosen because its shear strength was very similar to human bone, providing an accurate gauge of how bones would react in experiments. Buster's new flesh (with the exception of his face, hands, and feet) is made of a silicone marketed for use in animatronics called Dragon Skin. Buster's original head was retained when he was rebuilt, but it had to be replaced after it was shattered during a mishap on the Escape Slide Parachute Myth. His original face was retained to fit over his replacement head. They tested Buster 2.0 by dropping him 60 feet (about 20 meters) off a crane while inside a donated Cadillac named Earl.
The MythBusters have at times adapted Buster to fit specialized equipment or give him new functionality. For myths involving holding onto things (such as "Plywood Builder"), his hands are replaced with clamps or quick-release rigs. For myths involving falls (like "Hammer Bridge Drop"), monitoring equipment, such as accelerometers or shock gauges, is installed on or within his body. He was also attached to a pneumatic system at one time so he could punch sharks for the Shark Week special.
Just before testing the revisited "Jet Taxi" myth, Buster spoke two lines as chosen by fans: "Adam, I am your father," followed by "I wonder if Mike Rowe is hiring," a reference to the host of Discovery's other popular show, Dirty Jobs. In October 2007, the fan site also uploaded a video spoof of Buster's life narrated by Jim Forbes of Behind the Music and starring Tory, Grant, Kari and Adam.
As Grant once noted, there are very few times when Buster is actually used for his original purpose (a crash test dummy) on MythBusters.
Since his introduction on the show (in something of a running joke) the cast refer to Buster as if he were an actual living person, and consider him a full member of the cast in his own right. On several myths that involved long drops or intense forces in which Buster was damaged, Adam and others expressed dismay and concern over Buster having been damaged so extensively, most notably during Escape Slide Parachute.
On the Viewer Pick Special 2 episode, a new Buster was introduced. This Buster is a former crash test dummy provided by Dayton T. Brown, Inc. The new Buster was named "Buster 2.0" — not to be confused with the remodeled "Buster 1.0". The original Buster has been retired. During the James Bond Special, Buster was dressed up in a tuxedo when he was used for the exploding propane myth. In most myths involving people, Buster is usually dressed in whatever clothes are relevant to the myth (e.g. a police uniform, farmer's overalls, etc.) to give him more character and an air of faux authenticity. Buster has a extended family as well, added to the show in the plane crash episode, they consist of 3 simuaid dummies a man a woman and a child as well another child dummy used for seesaw saga.
In more recent episodes, the hosts of the show as well as the narrator appear to have taken up a policy of calling any human-analogue "Buster" (not just the specific crash test dummies given the name). However, this practice is very rarely, if at all, applied to ones that are made out of ballistics gel or ones that are otherwise used to represent human tissue (such as pigs).