Second Morbius

After being reduced to a disembodied brain by his botched execution, the exiled Time Lord criminal Morbius was given a new body by Mehendri Solon. Although not the product of regeneration, it was considered distinguishable enough from Morbius' original incarnation to appear separately from it as one of the faces in his mindbending duel with the Fourth Doctor.

Creation
After the execution of his original incarnation, Morbius's follower Mehendri Solon absconded with his still-living brain, which he kept alive in his secret laboratory on Karn.

Over the years, Solon acquired a great many body parts, which he used to create Morbius's new body. These included lungs from a Birastrop, a left arm from Solon's unknowing assistant Condo and a claw for his right arm. During this time, Morbius hid his presence from the Sisterhood by placing a barrier around his mind, and his hatred for them had increased. This plan to create a new body for Morbius and wreak vengeance was nearing completion when the Fourth Doctor and his companion Sarah Jane Smith arrived at his castle on Karn.

By this point, Morbius had become increasingly antagonistic towards Solon, frustrated by the scientist's never-ending promises. He didn't care about what he looked like in his new body, he only wished to walk, to feel and to see again. He likened himself to "a sponge beneath the sea", though he noted that a sponge had more life than what he was going through. He pitied his fate, which he saw as tragic, mourning that when he led the High Council on Gallifrey, he had "dreamed the greatest dreams of history". (TV: The Brain of Morbius)

A new body
The haphazardly-assembled body lacked a head to hold the brain of Morbius, so Solon planned to use the Doctor's head. After Morbius's brain was damaged during a fall when Condo fought with Solon on discovering his arm was being used, Solon was forced to use a plastic braincase. He had not used this before as there was the danger of a static electricity build-up which would probably damage the brain. Morbius was unable to speak for some time due to the damage sustained. Eventually, Solon was able to repair this but was killed soon afterwards when the Doctor poisoned him with cyanide gas. As Morbius proclaimed his return to power, he was challenged to a mindbending contest by the Doctor, who informed him that he doubted Morbius's power after his brain had spent so long trapped in the tank, and agreed.

Morbius was apparently winning the contest, but the static build-up left him in a dazed, animalistic state. He didn't speak again, only groaning in agony. Upon leaving Solon's castle, he was chased by the Sisterhood of Karn, surrounded and forced over the edge of a high cliff, apparently falling to his death. (TV: The Brain of Morbius)

Reduced to a brain once more
After the Doctor left Karn, the Sisterhood went to the bottom of the cliff and recovered what was left of Morbius' "not entirely destroyed" brain. Ohica led the wounded Morbius to the Death Zone to use the remains of Rassilon to give Morbius immortality. Ohica discovered that Iris Wildthyme had infiltrated the Sisterhood and used the Time Scoop to bring seven of Iris' own incarnations to Death Zone. The Irises were able to get past the Ice Warriors, Ogrons, Sea Devils, Zarbi, Mechanoids and Quarks that Ohica time scooped to the Death Zone and defeated Morbius before he gained immortality. (PROSE: Verdigris) This adventure would be often alluded to be Iris. (PROSE: The Scarlet Empress, The Blue Angel, Bafflement and Devotion, et al.)

Morbius cultists would later acquire fragments of Morbius's brain and use them to resurrect him in a new and more humanoid, though unstable, body. (AUDIO: The Vengeance of Morbius)

Legacy
In the video game Happy Deathday, played by Izzy Sinclair on the Time-Space Visualiser, Morbius was among a host of "every single enemy" that the Doctor had ever defeated, who were assembled by the Beige Guardian and pitted against the Doctor's first eight incarnations. (COMIC: Happy Deathday)

The TV show Doctor Who, which existed as a popular work of fiction on Earth, had featured "the Brain of Morbius" as an antagonist by 1981. (PROSE: Fanboys)

Appearance
The body built for Morbius by Solon was a lumbering, asymmetrical creature, (TV: The Brain of Morbius) a "hideous hybrid of alien life forms", made up of "bits of other creatures; (…) fur, scales and even feathers were jumbled together in a ghastly parody of life". (PROSE: The Brain of Morbius) His left arm was human, having been taken from Solon's assistant Condon while the right was an enormous, crab-like claw. With Solon unable to graft an organic head quickly enough to satisfy his master's wishes, the finished product utilised a clear glass brain-case to contain Morbius's original Gallifreyan brain, with two trumpet-like "horns" jutting out of it. (TV: The Brain of Morbius)

Personality
Following his long years of being trapped in a tank as a disembodied brain, the Second Morbius was a combination of depressed and vengeful, resenting the universe for what had happened to him. He retained his former arrogance, however, claiming that he was still "a Time Lord of the first rank" (something which the Fourth Doctor doubted). (TV: The Brain of Morbius)