Transformers: Prime S03E08 - Thirst

Knock Out is researching Ratchet's Synthetic Energon formula, and is using C.Y.L.A.S. (who is still implanted within Breakdown's corpse) as a test subject. The formula makes C.Y.L.A.S. extremely aggressive, so Starscream suggests injecting him with Dark Energon to make him easier to control. However, the mixture of the two Energons turns C.Y.L.A.S. into a mindless zombie craving fresh Energon, and he wanders the ship infecting any crew member he encounters by draining their Energon. After the incident, Knock Out must give all of his work to Shockwave, and Starscream gets beaten up by Megatron for starting this mess.

Deaths: Silas/C.Y.L.A.S.

Final appearances: Airachnid and Insecticons