The Transformers cartoonEdit
When Starscream was booted out of the Decepticon base for trying to overthrow Megatron (again), the once and future Air Commander found abandoned military vessels on Guadalcanal, dating from World War II. Realizing that he could build his own army with them, Starscream used the space bridge to travel to Cybertron to the Detention Center. After locating the personality components of the Combaticons in Cell 217, Starscream took them out of storage, then used the null-ray to destroy the containers carrying the others. Starscream is a bit of a dick.
When Shockwave discovered that some components were missing, he informed Megatron, who concluded that Optimus Prime and the Autobots were responsible, and attacked the Autobot base. Megatron is also a bit of a dick.