Bulkhead

Bulkhead is the name of three fictional characters from the Transformers series. All incarnations of Bulkhead are Autobots and are green in color. He was introduced in Transformers Energon and later redebuted in Transformers: Animated as a completely new character. The Animated Bulkhead became so popular that he was adapted to reappear in Transformers Prime. Whereas he was a minor character in Energon, the Animated/Prime Bulkhead appears as a main character in both series.

Animated series
Flashbacks in the episode "Autoboot Camp" reveal that Bulkhead was originally an energon farmer, who became a Space Bridge technician. He was given his name by Sentinel Prime, who referred to him as "all bulk and no brains." In boot camp, he met and befriended fellow recruit Bumblebee. As stated by Shockwave in "A Bridge too Close" Pt 1, it is revealed that Bulkhead scored higher than any other Autobot in a space bridge aptitude test, despite lacking any other seemingly discernible talent.