| Standard Alien | Ultimate Evolution | Key Episode Debut | | :--- | :--- | :--- | | Humungousaur | Ultimate Humungousaur (missile fists, armored shell) | “Ultimate Aggregor” | | Swampfire | Ultimate Swampfire (controlled fire bombs, enhanced regeneration) | “Too Hot to Handle” | | Echo Echo | Ultimate Echo Echo (metallic disc form, sonic disks) | “Night of the Living Nightmare” | | Cannonbolt | Ultimate Cannonbolt (spiked shell, faster roll) | “The Purge” | | Spider-Monkey | Ultimate Spider-Monkey (four-armed, feral predator style) | “Eye of the Beholder” |