In ‘Amazing Spider-Man’ (1984) #258, Spider-Man learns about the origin of the alien symbiote.

Spider-Man’s life has gotten more complicated after his time on Battleworld. He is divided between Mary Jane who just found out about him being Spider-Man and the Black Cat.

At night, Spider-Man is having nightmares and is sleep-walking above the rooftops of New York City.

Spider-Man slept through the day and wakes up from his nightmare sleep-walking with the symbiote. He decides to get some answers about his costume and heads to the Baxter Building, the base of the Fantastic Four. There, Spider-Man is greeted by H.U.B.E.R.T., the security robot. He is escorted to a room with advanced machinery and is greeted by the Human Torch. Spider-Man quickly explains that he wants his costume examined and Mister Fantastic agrees.

Mister Fantastic runs some tests and notices that the costume can mimic any shape that Spider-Man thinks of. After refreshments, Spider-Man and the Human Torch meet Mister Fantastic. Mister Fantastic explains his original theory was that Spider-Man’s costume was an alien material. In reality, his costume is a highly evolved symbiote that has attached to Spider-Man mentally and physically. Spider-Man exclaims: “You mean… It’s alive!”¹

Mister Fantastic suggests Spider-Man remove the symbiote immediately. Spider-Man agrees. Spider-Man tries with all his might to remove the costume, but the harder he tries, the stronger the symbiote attempts to attach to Spider-Man.

The Human Torch asks Mister Fantastic if he should burn off the symbiote. But Mister Fantastic says it might be too dangerous for Spider-Man. Stretching his hand through corridors, Mister Fantastic retrieves a sonic blaster. He blasts Spider-Man, the sonic waves remove the symbiote then Human Torch encircles the symbiote in a wall of flame. Then, Mister Fantastic traps the symbiote in a special container.