Igor was once a Decepticon, who ended up decapitated and getting its head reprogrammed, giving birth to Igor. After Starscream gave an opinion on Megatron's latest plan, Igor looked on as the Decepticon pummeled his underling for his insubordination. Transformers: Starscream
Igor hung around at Megatron's Decepticon refugee camp in Africa, where he was weird and crazy, eating the occasional minerals that Megatron gathered and brought back to him and the hatchlings. He would often be pleased at his master's return from excursions.
He later traveled with Starscream and his master to Washington, D.C., as the latter prepared to launch his invasion with the use of Sentinel Prime and his space bridge Pillars. After Megatron destroyed the statue of Abraham Lincolnseated on the Lincoln Memorial, Igor gnawed happily on its disembodied head.
Igor accompanied his master when the Decepticons invaded Chicago. Following the battle's end, he was last seen staring up at the sky, wondering what had become of his master.