Spiderman 3

"Venom" is actually an alien creature attached to a human.

It was advertently discovered originally by Robbie Jamieson (the astronaut son of Jonah) during a space flight (some comic storylines say the moon, other say on a comet.)

On the return trip to earth, the symbiote attempts to combine with the astronauts, causing the shuttle to crash. When Spidey comes to save the astronauts (which he successfully does), he comes into contact with the symbiote)

Now the rest might be movie spoilers so I'll cover them.

When Spidey sleeps that night, the symbiote merges with him physically. He wakes up hanging from a lightpost/building without knowing how he got there.

Over the next little while, he learns how to use the symbiote's different powers. His strength is far higher than it was before, he has much more web control and can even shapeshift.

However, a few days later while busting criminals, he finds himself filled with an incredible anger and desire to kill the criminals instead of bringing them in. He is able to resist the alien influence though and runs off.

Eventually, Spidey realises that he must get rid of the symbiote. He goes to a clocktower (early on, he discovered that large noises cause the symbiote pain) and uses the bell to forcibly remove it.

However, there it comes into contact with Brock who has always hated Spiderman and had followed him there. Instead of rejected the symbiote, Brock lets it control him since they share a common hatred of Spiderman.

Brock becomes Venom then. A creature of pure hate and malice with only two goals: killing Spiderman and, later on, propagating it's species.


Carnage is actually the same species as Venom but he is a merge of a symbiote and a homicidal maniac.