Spider-Man Unlimited is a short lived animated series featuring the Marvel comic book superhero Spider-Man. The series was released in 1999, and although it had fair ratings it was overshadowed by the main ratings grabber at the time, Pokémon, and was canceled after only a few episodes were aired. Fox later resumed airing the show, but aired only the first 13 episodes, cutting the show off on a cliffhanger. Several scripts written for Season 2, including the conclusion of the cliffhanger, were never produced.
With Jameson reluctant to return until the Evolutionary is defeated, Spider-Man elects to remain on Counter-Earth, blending in as best he can also as Peter Parker, and fighting Bestial versions of some of his greatest adversaries. It soon becomes clear also that Venom and Carnage are on Counter-Earth. This series also shows the animated version of Man-Wolf (John Jameson).
In issue #3, Peter is assigned by the Daily Byte to follow the Counter-Earth Version of Reed Richards. It is suspected that Reed has knowledge of a mysterious creature called the The Brute. The only thing Peter finds is that Richards is a really uptight individual. Together, they go to a party which requires everyone to have ID Chips. Before Peter is discovered not to have one, The Brute shows up to crash the party. After a fight between Spider-Man and The Brute, it is revealed to him that the creature is none other than Reed Richards. The Brute is helping the rebel against the Beastials; as Reed, he is a spy. He's also aided in his mission by his friend Ben Grimm. After a tested flight similar to the Fantastic Four's, Reed was transformed by cosmic rays into The Brute, Ben was unaffected, Johnny Storm was killed and Susan Richards was left in a coma.
Issue 4 introduced a sub-plot of humans and Beastials living in harmony in a hidden paradise called "Haven" which Spider-Man discovers, and stumbles on a human Gwen Stacy double, before he is driven from the place of solitude.
In the final issue he meets an escapee from Haven, a Bestial version of Wolverine. After fighting, the two team up and take down a Bestial Chameleon. It is hinted that Wolverine is really Naoko Jones' missing husband (although the cartoon hints that The Goblin is really Naoko's husband), but nothing came out of the storylines, as poor sales ended the comic's run.
Also, the powers of the symbiotes appear to have altered since the Spider-Man: TAS. In TAS, Venom has distinctly different powers from Carnage, because, as Baron Mordo explains to Cletus (Carnage's host) during the "Venom Returns" episode, the Carnage symbiote will grant powers "similar, but different; as different as you [Cletus] are from Brock." In TAS, Carnage was easily capable of producing axes, projectile darts, and other similar shapes with his symbiote. Venom was incapable of such feats. However, in Unlimited, Venom possesses powers that appear to share the same nature as Carnage's, allowing him to radically alter his body composition for shape creation and altering his body's format. Whilst both Carnage and Venom share this style of ability in Unlimited, it has also grown to be more extensive than what was displayed in the TAS. The pair could mold themselves into a "pool of symbiote" whilst moving freely, and even combine with each other via this technique to form one symbiote creature. Spider-Man notes this change in the first episode of Unlimited, when he is shocked to be flanked by this new power, Peter exclaims "Hey! You two could never morph like that before!" Despite this recognition of the change in the symbiote's powers, there is no explanation for this change.
Also of note, during the course of the TAS, Mary Jane, Venom and Carnage are all lost in dimensional portals, and Spider-Man himself goes searching for MJ across all of reality by the conclusion of the series. In Unlimited, their return to Earth is never explained, nor is it hinted that they ever went missing to begin with. This was to have been explained in a never created, sixth season of TAS, during which Spider-Man would have supposedly tracked Mary-Jane down to 19th Century England, and Carnage would have taken the mantle of Jack the Ripper, the symbiote having survived its destruction in the series finale.
Finally, the origins of the symbiotes are different in both shows. In Unlimited, it's revealed that the Symbiotes were originally insectoid creatures that infected Counter-Earth via a meteor shower, but that the mass extinction of Counter-Earth's dinosaurs drove them underground, where they evolved the ability to become semi-liquid like the Venom and Carnage symbiotes are (though there are still insectoid versions around that the Symbiotes use to infect the humans and Bestials). In TAS, this origin is never hinted at, and in fact it's suggested that they have always been a semi-liquid sentient goo.