The Low Kryten inserts the implant into Lister's spine.

The Spinal Implant was a device created by the Lows for controlling the body of another human

When Lister was captured by the Lows, they inserted their implant into his spine. It consisted of several needles which burrowed into the spinal cord at the victim's neck. It was apparently very painful to have it inserted, something the Lows enjoyed.

Using a handheld remote control, the Low Lister was then able to move his counterpart's body without his consent. They could make him do almost anything from the neck down, moving him in jerks and shuffles, but allowing him to speak and move his own head.

Firstly, they tortured him by making him slam his nose in a cupboard door, then burn his crotch with coffee and force his own mouth open to put in a tarantula. They explained that they wanted Starbug so that they could escape their decaying vessel.

Placing a large sticking plaster over his mouth, they sent him to kill his crewmates. Watching what he was doing through his own eyes via a video screen, the Lows made him brandish a knife at the High Lister, who thought he must be hungry. Lister could not warn his higher self and stabbed him twice. High Lister apologised for staining the knife with his blood, then keeled over dead. High Rimmer offered to provide Lister with a fresh knife, but Lister reached out and crushed his Light Bee, killing him.

Lister then advanced on the other Boys from the Dwarf. Cat ripped off the plaster, just in time for Lister to warn him that he was going to kill him with a fire axe. Cat dodged the blow, but Kryten got hit twice. The Lows then made Lister start strangling the Cat. Rimmer suggested blowing Lister's kneecaps off to incapacitate him, but Cat simply kneed him in the groin. Lister then grabbed a bazookoid and shot at the others, but he was able to call out where his shots would land. This allowed enough time for Kryten to circle behind Lister and render him unconscious with chloroform.

Kryten and The Cat put him aboard Starbug while they escaped the Low Red Dwarf, but despite being unconscious, Lister was still under remote control. He smashed up the controls in Starbug's cockpit before attacking The Cat again. Kryten spotted the implant in Lister's neck and pulled it out, but as Starbug careered out of control, the implant was pushed into The Cat's neck. He attacked Lister before Kryten pulled the implant out again and threw it into the mid-section.

As soon as the original Red Dwarf was recreated and Holly had taken control of Starbug, Lister relaxed and sat down in the mid-section - right on top of the spinal implant. With his body back under remote control, he advanced on the Dwarfers, but Kryten wondered who could be controlling him now that the Low Red Dwarf had ceased to be. Cat noticed laughter coming from the cupboard and shot his bazookoid through the door, killing the stowaway Low Lister. Kryten suggested destroying the implant for good, but Cat asked him for just one week with the remote control, making Lister slap himself for Cat and Rimmer's amusement ("Demons & Angels").