Complex sentence: He and Sloane attempt to use Anti-Venom to kill Spider-Man, but when Spider-Man 2099 intervenes, Octavius, Sloan and Anti-Venom are merged and thrown into a time portal, where they are trapped between the present time and the year 2099.
Split into simpler sentences: He and Sloane attempt to use Anti-Venom to kill Spider-Man. But when Spider-Man 2099 intervenes, Doctor Octopus, Sloan and Anti-Venom are merged and thrown into a time portal where they are trapped between the present time and the year 2099.