Venom (Eddie Brock) is a comic book anti-hero in the Marvel Comics universe, and an enemy of Spider-Man. He is usually counted as one of the web-slinger's greatest enemies, alongside Dr. Octopus and the Green Goblin. Publisher Marvel Comics - First appearance Amazing Spider-Man #252 (alien symbiote) Amazing Spider-Man #298 (as Venom) Created by David Michelinie Todd McFarlane A human host linked to an alien symbiote whose previous link with Spider-Man created the equivalents of his abilities. In addition, the being can produce its webbing, change its appearance and cannot be detected by Spider-Man's spider-sense. http://en.wikipedia.org/wiki/Venom_%28comics%29

While embroiled in a major crossover storyline fighting the Secret Wars on an alien planet, Spider-Man had to give up his web shooters to help the heroes escape being crushed by a mountain (dropped on them by the Molecule Man). Needing to find equipment to replace his web shooters, Spider-Man was informed by other heroes of a machine in a nearby lab that could repair his suit. Spidey went searching, but unwittingly activated the wrong machine, freeing from imprisonment a sentient alien symbiote. As Spider-Man touched the black blob, it flowed over his body, forming a new costume which he soon discovered responded to his thoughts, was able to mimic street clothes and seemed to provide an inexhaustible supply of webbing. Once back on Earth, Spider-Man learned the true nature of the costume, and discovered that the symbiote desired to fuse permanently with him, enveloping him at night as he slept, using his unconscious body to go out and fight crime. With the aid of Mister Fantastic, Spider-Man removed the costume by using sonic waves, to which it was vulnerable, but it broke free from the Fantastic Four's custody, and attempted to bond itself to Spider-Man in a church tower. The clanging of the church bells, coupled with Spidey's forced rejection of the symbiote, weakened the alien, and it slithered away, apparently to die. Meanwhile, reporter Eddie Brock (born in San Francisco, California to Carl and Janine Brock) had been penning a number of articles in The Daily Globe on the recent Sin-Eater case, a storyline that ran in Amazing Spider-Man’s sister title, The Spectacular Spider-Man. Following a false lead, he proceeded to write a series of columns identifying Emil Gregg as the perpetrator of the crimes. When Spider-Man caught the real criminal, policeman Stan Carter, Emil Gregg was discovered to be a compulsive confessor. The Globe became a laughing stock, and it fired Brock, who was shunned by his peers, and forced to write scathing celebrity exposes and alien abduction drivel for the scandal rags. Brock took up weight lifting in the hopes of reducing his stress, but was unsuccessful in alleviating his obsessive hatred of Spider-Man. Planning to kill himself, Eddie went to a church to apologize to God for not being strong enough to handle life. In that church, Eddie was found by the alien costume, which bonded itself to the failed reporter. The process left both, already emotionally unstable individuals, permanently damaged. Adopting the name Venom in reference to the tawdry stories he was forced to write after falling from grace as a reporter, the new symbiotic pair decided to take their revenge on Spider-Man.

Though it should be noted that most recently, the identity of Venom has been adopted by Mac Gargan who was formerly the villain known as scorpion. The alien symbiote bonded with Mac Gargan and created a new Venom persona when Brock was dying of cancer