On Earth-89721 a man known as the High-Evolutionary exploded his “genetic bomb” in Earth’s Atmosphere. While Humanity did evolve further, many already super powered people, both heroes and villains alike, evolved and mutated in drastic ways, gaining immense powers. Spider-Man was one of these people, and he gained 6 extra arms for a total of 8, and could produce organic webbing from all of them. Considering what happens next, he may even have more powers, but it isn’t stated.
The super evolved heroes and villains were now known as the “Godlike Ones” and they all left Earth, leaving the planet to the new Humanity. They traveled through space and accomplished many amazing feats, such as destroying Galactus and his Herald, and even defeating the cosmic beings known as Death and Eternity. They then used their powers to merge with Death and Eternity into a single being and left known reality to create a new dimension and sacrificed themselves to create a new universe.
Positively Jim 