Their alliances usually spring from a common enemy. Carnage, born from the Venom symbiote, is a monster so dangerous that Spider-Man and Venom repeatedly bury the hatchet to stop him, most famously in the sprawling Maximum Carnage story. When the symbiote god Knull came for Earth, the two lined up together again.
The trust never fully takes hold, and that is the fun of it. Venom will guard the innocent, then remind Spider-Man in the same breath how much he still resents him. It is a team-up built on grudging respect, shared history, and the knowledge that when the world is truly in danger, even enemies can pull in the same direction.
The bond began years before Eddie Brock. During the Secret Wars, Spider-Man picked up a sleek black costume on an alien world (Secret Wars #8, 1984), only to discover it was a living symbiote that wanted to fuse with him permanently. Peter rejected it, driving it off. Meanwhile Eddie Brock, a disgraced Daily Globe reporter, blamed Spider-Man for wrecking his career after Spidey exposed his big scoop about the Sin-Eater as false. Consumed by hatred, Brock encountered the abandoned symbiote in a church. It still carried Peter's memories and shared Brock's rage, so the two joined into a single creature that knew all of Spider-Man's secrets, including his identity. They stalked and ambushed him as Venom in The Amazing Spider-Man #300 (1988).
In recent comics the Eddie Brock story moved well beyond simple hero-versus-villain. After the King in Black saga, Eddie ascended to a god-like role connected to the symbiote hive, while his son Dylan Brock took up the Venom mantle on the streets. Spider-Man and the Venom legacy still cross paths whenever Carnage or the larger symbiote threats resurface, and the relationship remains what it has always been: former enemies who trust each other just enough to fight side by side when the stakes are high enough.
Venom is the fusion of two things: an alien symbiote and a human host. The symbiote is a living costume Spider-Man first wore as a sleek black suit before learning it was alive and rejecting it. Cast off and full of Peter's memories, it found Eddie Brock, a disgraced reporter who blamed Spider-Man for ruining his career. Their shared resentment made them a perfect, dangerous match.
Together they became Venom: bigger and stronger than Spider-Man, able to crawl walls, fire webbing and tendrils, and slip past Spider-Man's danger sense because the suit was once his. Over time Venom shifted from pure villain to a self-styled 'Lethal Protector,' guarding innocents in his own violent way while never quite letting go of his grudge.