Energon Eater

Energon eaters are giant eel-like aliens dwelling in the galaxy, they feed off energon from ships the capture and hunt by scent largely as they can smell flowing  energon nearby. They can also control energon to drawn other ships to their distress calls.

Description
An ''Energon eater resembles a giant large moray eel and has pitch black grey skin with white spots and long antenna. Though they have no eyes, making them blind, therefore they fine prey with the smell of ''flowing energon.  They also have energon powered tails that allow them to take control of ships fuelled by energon, it also known when Energon eaters do come across Cybertronians, they wouldn't stop hunting them until it finishes them off.

Rescue Bots cartoon
In "Unfinished Business", the Sigma and its crew of Rescue Bots followed a distress call to a damaged ship, only to be confronted by an Energon eater. Heatwave, Blades, and Boulder headed back towards the ship, but were cut off by the creature until Chase  soon impacted the ship directly into it. With everyone back on board the Sigma, they realized that the Energon eater would continue hunting them, so they had no choice but to put themselves in stasis and shut down the ship to eliminate the energy signature, and the beast left them alone. Some time later, after the Rescue Bots had made a home on Earth, Chase had the urge to again try to aid the stricken ship. He and Boulder took the Sigma back to the scene, only to find that the Energon eater had been powering the derelict's computer to make it produce a distress signal. The pair managed to evade the beast, but it drained the Sigma's power core, leaving the ship dead. Chase and Boulder were forced to trap the Energon eater and use power from it to reenergize the ship. They took the creature back to Earth and presented it to Optimus Prime.