Energy vampire

Energy vampires are... something from the Generation 1 continuity family.

'Cause this is Thriller! Thriller night!

An energy vampire is a Transformer who has had his or her energy drained by the monstrous beast known as the Dweller. Upon contact with the Dweller, Transformers become gray-skinned, red-eyed, and mindless. They begin shambling around, drawn towards those who have not yet been turned. Simply touching another Transformer spreads the malady. Ultimately, they all return to the Dweller, delivering their captured energy to it.

According to Perceptor, this phenomenon is a form of energy depletion, turning the affected into energy leeches. He correctly theorized that a massive energy infusion could return a vampirized Transformer to normal.

Fiction

The Transformers cartoon

Once the Dweller was released from its prison, it began draining the energy of any Transformer it attacked. Those who suffered from the attacks became energy vampires which began to attack others on Cybertron. The Dweller in the Depths

Cybertron Comic

Scorponok awakened on Cybertron with a thirst for Energon and living Sparks. Balancing Act, Part 2 Ramjet commented that he had seen Spark maladies of this sort before, and that Scorponok's victims would become energy vampires themselves. Balancing Act, Part 3 Vector Prime believed that something might have been done to help Scorponok, had they possessed a Cyber Planet Key. Balancing Act, Part 4