Soundwave

Soundwave was Megatron's right-hand bot, frequently sent on important reconnaissance missions with his cassettes, and often playing a key role in many schemes against the Autobots.

On Cybertron, he used his ability to transform into a roadside fixture to spy on the Autobot city of Iacon, learning of the Autobots' plan to search for energy on other worlds. Joining in Megatron's attack on the Autobots' craft, the Ark, Soundwave fell to the same fate as the rest of the ship's occupants when the craft crashed on prehistoric Earth, entombing everyone within in stasis. Immediately after the Transformers awakened on Earth in 1984, Soundwave played an essential role in the generation of energon cubes and the formation of plans for a new space cruiser to return the Decepticons to Cybertron.

Later, he used his mind-reading talents to acquire an antimatter formula for the Decepticons from the brain of Chip Chase. He and his cassette minions were often on spying missions against the Autobots.