Spider-Man Unlimited: Season 2: Episode 6: The Finale

Basically, what happens in this episode is that the Human Resistance finds out that Karen O'Malley was brainwashed into becoming the second High Evolutionary. In a climactic battle against her and her forces, the Resistance wins and John Jameson manages to make Karen human again, while the first High Evolutionary and his Knights of Wundagore are all killed. Spider-Man manages to permanently defeat Venom and Carnage, along with the symbiote-possessed versions of the Rhino and Shocker and Venom and Carnage's flunkies in their bid to restart the Synaptic.

The episode, and the series, ends with John Jameson sending out a signal back to Earth saying that he and Spider-Man will remain on Counter-Earth for the rest of their lives (Spider-Man agrees to this because after figuring out that Mary Jane betrayed him to the Kingpin last episode, he's got nothing more than to be a hero on Counter-Earth's New York). With that, as John finally hooks up with Karen, and Counter-Earth is truly at peace, with humans and Beastials alike in harmony for good this time, the final shot would have Spider-Man swinging off into a sunset dawning on Counter-Earth's New York.