Resident chemist and explosives expert for the elite among the Constructicons, Mixmaster has spent his entire life learning all there is to know about chemical interaction. He can make thousands of poisons, explosives and deadly gases from the materials around him. The other Decepticons rely on him to fashion powerful warheads for their missiles and dangerous venom in which to coat their blades.
Revenge of the Fallen film
At one point, he, Skipjack, Long Haul, Ravage, and Scrapmetal dive into Laurentian Abyss to locate Megatron's corpse. After killing Scrapmetal, they succeed in reactivating their fallen leader with the help of the Doctor.
Later, he stands atop Brooklyn bridge, and knocks down one of the U.S. flag poles, in a show of dominance.
During the battle in Egypt, a decepticon with the same body type as Mixmaster's met up with the other Constructicons to form Devastator. Meanwhile, the real Mixmaster was attacking N.E.S.T forces. After a tank shot off one of his shields, Mixmaster transformed into Cannon Mode and destroyed the tank. Jetfire arrives however, and Mixmaster couldn't hold him off. He attempted to shoot him, but Jetfire killed him by slicing him in half, and kicking his head off.
Dark of The Moon game
Mixmaster mysteriously returns in the Dark of The Moon prequel game leading a group of Decepticons in an attack on the American city of Detriot. When Ratchet goes to investigate unusual activity in a human factory, Mixmaster's Decepticon soldiers launch an ambush on the Autobot medic. Eventually, Mixmaster is seen assaulting Ratchet and Ironhide shows up and demands the Constructicon to release his fellow Autobot. He does so by throwing him viciously against a wall leaving him heavily damaged. He then orders the other Decepticons to kill Ironhide. That backfires as the Autobot defeats and kills all of them, leaving Mixmaster no choice but to fight Ironhide himself. During the battle Mixmaster states Ironhide cannot pierce his shields. Ironhide then proceeds by destroying the gears upholding the cargo lift in the very room dropping Mixmaster to the bottom of the factory. He survives and retreats to the scrapyard near the building. When Ironhide arrives at the scrapyard, Mixmaster grabs him through a wall and tosses him into the open area. The Autobot has possession of the Heavy Iron 2.0 weapon and is able to destroy Mixmaster's shields in the fight. The Constructicon is eventually immobilized on the ground and Ironhide proceeds to kill Mixmaster by shooting him in the head with his new weapon.