Cliffjumper

Cliffjumper is a paranoid, trigger-happy jerk who despises Decepticons and TRAITORS! He has the miraculous power of pulling giant guns from nowhere and has tendency to be shoot first and talk later. He also gets mistaken for Bumblebee a lot. He also killed Breakdown.

Killing Breakdown
A some point during the war, Cliffjumper led a squad of Autobots to destroy any Decepticon patrols that they found. They also happened to be high on Syk, a type of drug. So when they found Breakdown's patrol, they ripped them to shreds and used their remains as decorations.

Traitor Incident
At some point, Cliffjumper accused Mirage of being a traitor but his was proven to be false. Later on, when it was proven that Doubledealer was a Decepticon spy, Cliffjumper hunted him down a killed him singlehandedly. He then created a list of suspected traitors, this list happened to include around 90% of the Autobot cause. Man he has trust issues.