Venom is a Marvel Comics character, and arguably one of the most famous of Spider-Man's Rogues Gallery, though over time his character and motivation have evolved. To date there have been four different men and two women who have assumed the mantle of Venom. The Eddie Brock version of the character was playable in the video game adaptation to the Maximum Carnage story arc, then in Separation Anxiety, and later, the first and second Marvel vs. Capcom, making the leap from comic to video game. Mac Gargan was playable as Venom in the second Marvel Ultimate Alliance game, with Eddie Brock's appearance as an alternate costume. Brock, as Anti-Venom, is an antagonist in Spider-Man: Edge of Time, marking that version of the character's first appearance in a video-game.Venom's origin began with an alien symbiote that was used to build a new suit for Spider-Man, inspired design-wise by the second Spider-Woman (Julia Carpenter) during their team-up in Secret Wars. The costume change was initially unpopular with fans (although the black costume would later be brought back as fans began to like it a bit more) so it quickly went through a Retcon as an alien symbiote that wanted to bond with Peter Parker. Horrified, Spidey managed to repel the symbiote by taking advantage of its weakness to sonic noises via church bells. Some writers and editors did not like Peter's motivation at the time so there was a second Retcon that the suit was more powerful than his ordinary suit, but was slowly driving him insane with rage.The creature ultimately survived, going on to bond to a series of hosts (many that bore grudges against Spider-Man), developing from a lonely alien creature to a bloodthirsty monstrosity, and remains one of Spider-Man's deadliest foes, despite of and due to the lingering desire it still possesses for him. Its popularity among creators and fans has made it among the most memorable of Spider-Man's Rogues Gallery. Currently it is bonded to long-time Spider-Man supporting character Flash Thompson, and as such featured in Venom Volume 2 and Thunderbolts Volume 2. After Venom Vol. 2 was cancelled, Flash appeared in the "Darkest Hours" Superior Spider-Man story arc, and worked with Scarlet Spider to save the Microverse from Carnage. Agent Venom then went on to join the Guardians of the Galaxy; while it was initially hinted that Flash might not be the one wearing the symbiote, this was ultimately proven not to be the case.The symbiote remaining bonded to Spider-Man or bonding to a character other than Eddie Brock has been the focus of numerous What Ifs, and alternate versions of the character are present in alternate universes, most prominently in Ultimate Marvel and Marvel 2099.Venom has so far had three entries into Marvel Avengers Alliance - Mac Gargan Venom appears as a boss, Flash Thompson as Agent Venom was added as a playable character in December 2013 (though Mac Gargan is still Venom as well, according to Spec Ops 18, where the two Venoms meet face to face), and Eddie Brock as Anti-Venom was added as a playable character in May 2014.In animated adaptations of Spider-Man featuring the character, the Eddie Brock version of Venom has been the sole version to appear until Ultimate Spider-Man, in which an adaptation of the Ultimate Marvel version of Venom appeared with Harry Osborn of all people as its host. In season 3, Flash Thompson takes up the mantle as Agent Venom and becomes an Agent of S.H.I.E.L.D.Eddie Brock appeared in Spider-Man 3, acquiring the symbiote late in the film before being killed. Sony has announced that Venom will be getting a spinoff film set, tentatively titled Venom: Carnage, in The Amazing Spider-Man Series. No word yet on who will be wearing the suit or, judging by the Oscorp Meta Origin running throughout the series, whether Peter will even wear the suit this time, although Eddie Brock has been introduced in promotional material.For tropes related to the symbiote itself, individual hosts, and characters from the series, there is a Character Sheet here.
Spider-Man: Edge of Time: Symbiote Spider-Man and Poison (as DLC) are alternate skins, and Anti-Venom is a main antagonist.
Marvel Avengers Alliance: The Black Suit is an alternate skin for Spider-Man, and Eddie Brock/Anti-Venom and Flash Thompson/Agent Venom are unlockable characters. The Mac Gargan Venom appears as a recurring boss, and Hybrid, Scream and Carnage are bosses in SpecOps 18: Symbiosis.
The Amazing Spider-Man: The Venom symbiote was discovered and bonded to the Scorpion (here a human/scorpion cross-breed) by Oscorp.
The Amazing Spiderman 2: The synthetic Black Suit is an alternate costume for Spider-Man in the console versions, and the "Venom Project" plays a major role in the final arc of the game. Venom appears as a boss and Symbiote Spider-Man is an alternate costume in the iOS and Android versions. Spider-Carnage is an unlockable costume.
Marvel Comics 2: Eddie had died at an unspecified point, and the symbiote was captured by S.H.I.E.L.D.. After escaping custody, the symbiote tracks down and possesses the retired Peter, creating "Spider-Venom◊". Peter is freed by the combined efforts of Spider-Girl (his daughter, Mayday) and Phil Ulrich, and the symbiote falls into the hands of the Goblin Queen, who sics it on Normie Osborne in a plot to convert him to her side. After an intense struggle, Normie overpowers and gradually rehabilitates the symbiote, which goes on to sacrifice itself in an attempt to stop the Hobgoblin.
In Spider-Man: Fairy Tales #3 Venom is a Tsuchigumo responsible for the deaths of Izumi's parents and uncle. In an attempt to corrupt Izumi, it bit him, giving him an arachnid-based appearance, and the customary spider powers.
Marvel Mangaverse: Venom is Peter's cousin, an exiled member of the Spider Clan, and the one who killed Peter's Uncle Ben, wearing a uniform similar in appearance to Symbiote Spider-Man. The symbiote itself appears as a cursed amulet that takes over Peter, turning his costume black and making him more aggressive, but Venom sacrifices himself to free Peter from its influence and redeem himself. He later reappears in a more monstrous form and becomes Peter's sensei.
Marvel Zombies: Eddie is a zombie, and the symbiote (one of the few entities immune to the plague) is dying due to a lack of viable hosts.
Old Man Logan: The symbiote is stalking Wolverine and Hawkeye, and eventually attacks them after possessing a T-rex.
Spider-Man India:Nalin Oberoi's attempt to corrupt Pavitr Prabhakar with an evil amulet causes Prabhakar to briefly look like Venom. Pavitr destroys the amulet, but the evil reforms as a Blob Monster elsewhere.
Spider-Man/Red Sonja: Venom is manipulated into going after Spider-Man and Red Sonja by Kulan Gath, who later takes the symbiote from Eddie, and forcibly bonds with it to become "Kulan Venom".
Venom: Man-Spider and the Red Ssssonjaa!!! My master calls for thy blood!
Spider-Man: Venom?! And he's talking all Tolkieny?
Reign: Posing as "Edward Saks", Venom takes over New York City following Spider-Man's retirement and sets up a number of provisions in preparation for his eventual return: re-enlisting the "Sinner Six", replicating his symbiote thousands of times, and building a security system called "WEBB" that prevents New York citizens from escaping from the city.
Rune vs. Venom: A symbiote that survived Planet of the Symbiotes thanks to possessing Malibu Comics character Rune tries to instigate another invasion, and avenge the failure of the first one by killing "race traitor" Venom.
Ultimate Marvel: The "Venom Suit" is a bio-engineered protoplasmic entity created as a cancer cure. Unfortunately, this "symbiote" is unfinished and genetically tailored to the Parker family's DNA, so it starts devouring any other host that tries to wear it (like Ultimate Eddie Brock) forcing them to consume the biomass of other beings to survive.
What If?: Too many to list, but some prominent ones are:
What If... Venom Had Possessed the Punisher: Frank Castle reaches the church shortly before Eddie Brock does and bonds with the symbiote, eventually subjugating it and going on to become more lethal than ever.
What If the Alien Costume Had Possessed Spider-Man?: The symbiote remains bonded to Peter Parker, aging him at an accelerated rate until he dies. The symbiote bonds to the Hulk, explaining that it didn't want to kill Peter and is curing Bruce Banner to redeem itself, but Thor attacks Venom-Hulk and winds up bonded to it himself. Black Bolt removes the symbiote, but before it can be imprisoned Black Cat kills it to avenge Peter Parker's death.
What If? Brave New World: When the Secret War participants are trapped on Battleworld, the symbiote bonds mind and body to Peter Parker, leaving him a skeleton with the symbiote's biomass forming their body.
What If? Spider-Man: The Other: Following his "death" at the hands of Morlun, Peter rejects embracing the Other and kills his Inner Spider, leaving his metamorphosis incomplete. The Venom symbiote senses this and abandons Mac Gargan to rejoin with its first host and finish his transformation, creating a new being called Poison.
What if the Venom Symbiote Possessed Deadpool?: Deadpool bonds with the Venom symbiote after killing Spider-Man, becoming Venompool. After numerous shenanigans, Venompool destroyed his home universe with the Recton Expungifier, but was later shown as a member of Dreadpool's Evil Deadpool Corps, being killed in Deadpool Kills Deadpool Vol. 1 #4.
Always Chaotic Evil/Horde of Alien Locusts: The symbiotes, Depending on the Writer, are always evil and make their hosts go crazy or they feed off negative emotions, but in either case, they are not nice. The Venom symbiote and its progeny are apparently the only ones who care for their hosts. Of course, even then, the Venom symbiote is often depicted as the insanely jealous type.
Angel Face, Demon Face: The way Venom looks ties closely with the relative morality of the symbiote's host. On the heroic side, Peter's suit looks more or less like his usual costume but in black; heroic soldier Flash Thompson wears what looks like body armor (unless he loses his temper); and in the Spider-Girl series, Normie Osborn had what looked like the usual suit but with his face visible underneath and no fangs. On the evil side of things, Eddie Brock's costume has More Teeth than the Osmond Family and a lolling tongue; and when the eviler Mac Gargan wears the symbiote it looks even more freaky and bestial than Brock's usual version (unless he uses a Power Limiter).
During the Minimum Carnage arc, Marquis Radu creates clones of the Venom and Carnage symbiotes in the body banks and fuses them together. Carnage cheerfully dubs the union incestuous and seizes control of the clones to kill Venom.
Kristoff von Doom made an army of clones, stuck them in a bomb, and dropped it on New York.
Denser and Wackier: Almost all of the stories written by Larry Hama, which featured things like a cyberspace showdown between Venom and Carnage, Venom being assigned to take out the nefarious Doctor Yes, and Venom and Scream teaming up with a group of Totally Radical skateboarders to kill a dapper symbiote-eating alien.
The Dreaded: Symbiotes in general appear to be one of the Marvel Universe's alpha predators, conquering entire worlds. On Earth, Venom inspires at the very least anxiety among other villains due to the hosts' monstrous appearance and reputation for eating people, and Carnage is powerful enough to take on the Avengers and win.
Fangs Are Evil: Most incarnations of Venom manifest a huge mouth full of pointy teeth, especially when the symbiote takes over its host. That said, it didn't have fangs when it first bonded to Peter. Mac Gargan as the Sinister Spider-Man, Flash as Agent Venom, and SpOck as Superior Venom also had smooth masks as long as they keep the symbiote under control, although they could form toothy jaws at will to either scare or eat opponents.
Legacy Character: Of a sort, as the symbiote has had four main hosts all claiming the title of "Venom".
Let's You and Him Fight: Most of the Venom comics in the 1990's had Eddie Brock fighting another antihero before having to team up with them.
Lost in Imitation: The idea that the symbiote was turning Peter evil as part of its efforts to merge with him stems from the 1994 Spiderman The Animated Series cartoon, and was promptly adopted into the comics due to the fact that the initial depiction of the seperation kind of made Peter look like the bad guy.
Monstrous Humanoid: The symbiotes transform their hosts' bodies, giving them huge mouths lined with fangs, claws on their fingers (and occasionally toes), and the ability to project pseudopods and transform their limbs into simple weaponry.
Muscles Are Meaningful: The symbiote significantly bulks its host up, although Flash's default form is more Heroic Build. In an early appearance Brock mentions that the suit amplifies his own strength, so if the host gets stronger, Venom becomes exponentially stronger. This is more evident with Mac Gargan, whose strength was amplified from 15 tons to 60 tons by the symbiote.
Mythology Gag: The bewildered self-examinatory pose Spider-Man is striking on the cover of Marvel Super Heroes Secret Wars Vol 1 #8, which explains how he got the symbiote, has been used at least three other times: once by Mac Gargan after becoming the Sinister Spider-Man, once as a parody on a cover of Marvel Zombies, and once by Ai Apaec when Norman Osborn turned him into a six-armed Black Suit Spider-Man lookalike.
Nineties Anti-Hero: Although most incarnations of the character are villains, Venom had his phases in this time, notably pulling a few Enemy Mines with Spidey.
One-Winged Angel: Since Venom's first solo mini, most incarnations have been known to pull one of these off at times when they really lose control.
Planet of Copyhats: All of the symbiotes on the cover of Guardians of the Galaxy Vol. 3 #21 are black with white spider-emblems.
Royal "We": Eddie Brock tended to refer to himself in first person plural pronouns while bonded with the symbiote, and on those occasions where he referred to himself in the singular, he would call the symbiote "My Other". However, subsequent hosts have tended to avert this.
Synchronization: Even if physically separated from their respective symbiotes, Eddie and Cletus maintain a mental connection to them, feeling their emotions and injuries, seeing what they do, etc. This no longer appears to be the case with Eddie and the Venom symbiote, however.
Teleporters and Transporters: The symbiotes have spaceships, but their primary means of invading other worlds is with Stargate-like portals. The first wave in Planet of the Symbiotes built one, and the possessed Rune constructed another in Rune vs. Venom.
Whole Plot Reference: License to Kill was an homage to the James Bond franchise, the first 1/3 of the Daniel Way series is clearly based on The Thing, and the Seed of Darkness prequel was a throwback to the "Marvel Monsters" epics of the 1950s, with Eddie as The Everyman protagonist.