Mindworm was a superhuman mutant with limited telephatic powers who was briefly a minor enemy of Spider-Man. He had an oversized cranium and was naturally extremely intelligent. Eventually, Mindworm attempted to reform but his problems were too difficult for him to control and he allowed himself to be killed by common street thugs to end his great suffering.

C.M. Kornbluth published a science fiction short story in 1950 with the title The Mindworm. The center character of this was a mutant who fed (fatally) on others' emotions. The Marvel character of that name has very similar abilities. He is also mentally ill, suffering from severe debilitating chronic depression and light dementia.

Born a freak with superhuman powers, William Turner accidentally killed his mother through his unconscious vampiric psionic feeding, which caused his father to go into emotional shock and run in front of a car. The effect of this incident was extremely traumatic for young William as he deeply cared about both of his parents and did not even know he was a mutant when the incident occurred. It was revealed that his mutation was a result of an experimental compound being stored near the hospital where he was born. After the death of his parents, he was sent to an orphanage, where he protected himself from bullies with his powers. People soon started calling him "Mindworm". While in the orphanage, William managed to self-educate himself to a considerable degree, being quite brilliant.

After he grew up, he moved into a small shack on the outskirts of New York City, where he secretly fed off of the emotions of local tenants, but not to the degree of fatally injuring them. Flash Thompson lived in an apartment near him. Later, Peter Parker had to move in with Flash, and so Mindworm attempted to feed off Parker. However, Parker was able to resist Mindworm with his strong mind. Mindworm eventually physically attacked Parker, but Spider-Man gave him a severe blow to the head, which completely stunned Mindworm and allowed the police to imprison him. Mindworm never emotionally drained his victims to the point of killing them and had no other way to sustain himself.

Mindworm once attempted to avenge himself on Spider-Man, but when he fought Spider-Man in a dream he realized all of his criminal actions were spawned from his anguish over his parent's deaths. Finally, he befriended Peter and adopted the motto "With great power comes great responsibility".

Unfortunately, Mindworm's impressionability and loneliness were later exploited by criminals who used him to assist in a robbery and he was again imprisoned. This time, while in prison, Mindworm began to exhibit signs of extreme mental illness. When he was released, he could not work or sustain himself and became homeless. He was preyed upon by local hoodlums and not wanting to use his powers to injure others he would not defend himself. Spider-Man noticed Mind-Worm's plight but was unsure how to help him. Before Spider-Man could act, Mindworm was killed by a street gang.

Mindworm was a mutant with the ability to drain mental energy from humans around him. He could also read minds and was moderately telepathic. His psionic abilities manifested themselves in several ways, such as being able to cast vivid illusions, fire destructive "mind waves" at his enemies, invade dreams, and he could drain mental energy to the point of death. He could also augment his physical strength to temporarily enhanced levels by absorbing psychic energy. He even made himself strong enough to fight Spider-Man at one time.

He was also probably a natural genius, but his severe mental illness and the destructive nature of his mutation inhibited him from ever being able to properly educate himself to a degree that corresponded with his natural mental giftedness. He was once also highly physically athletic.