Rampage is a Predacon who works for Megatron. Rampage (also known as Protoform X) is the awful result of scientific experimentation gone awry. He is a serial killer and cannibal, with an immortal spark that ensures his twisted brand of horror and misery will live on as long as he does (forever, presumably). Though hard to destroy Rampage's Spark is not completely invincible. As shown during his fight with his old enemy, Depth Charge, Rampage's Spark can be destroyed when pierced by raw Energon (though it is unknown if this is because the Spark was experimental or Energon is so powerful in its raw state). Rampage detects and draws strength from the emotions of others, literally feeding on the pain and suffering he causes. As an unwilling conscript of the Predacons, he is contemptuous (at best) of the rest of his team, typically bored and uncooperative on missions, and he frequently sneaks off for his own purposes to try to relieve his boredom in the most cruel and horrible ways possible.
Protoform X was a Maximal experiment to recreate Starscream 's mutant, immortal Spark. Though arguably successful in this regard, the creation was unstable. In point of fact, he was criminally insane. He destroyed Colony Omicron, killing all of its inhabitants save a lone security officer, Depth Charge, who eventually tracked him down and captured him - but not before Protoform X destroyed Starbase Rugby and devoured an unknown number of the inhabitants. As he couldn't be destroyed, the Maximal Elders had Protoform X placed into a stasis pod that would be stored within an exploration vessel, the Axalon, with instructions to its commander to dump the stasis pod on some barren world in deep space.
Protoform X was among the stasis pods jettisoned by Optimus when the Axalon was damaged by Megatron's Predacons, and only fell out of orbit far into the Beast Wars. While scanning a beast mode, X was taken offline by the transwarp explosion that converted his body into a transmetal one. Though thought to be dead, he was eventually revitalised when the battle near his stasis pod caused an Energon storm that shocked him into activation, and he promptly set out to terrorize all nearby Transformers, ripping Tarantulasto pieces before stalking Blackarachnia and Silverbolt. X seemed unstoppable at first, easily withstanding a mass assault from Optimus Primal, Cheetor and Blackarachnia that knocked him off the edge of a cliff, but when one of Silverbolt's missiles jammed his tank treads as he climbed up a mountainside, he lost his grip and tumbled even further down the rock face, landing at the bottom in pieces.
As Protoform X lay immobilized, Megatron arrived and, using a blade of pure energon, removed a portion of his indestructible spark. Megatron then had him brought back to the Predacon base and repaired. When X attempted to turn his weapons on his "savior", Megatron revealed that he held half of X's spark in a special cage lined with energon crystals, allowing him to torture the beast at will. With his 'loyalty' thus assured, Megatron welcomed Protoform X into the Predacon fold, dubbing him "Rampage".
Rampage made no secret of his hatred for his new "master". Megatron kept the spark cage with him at all times, fending off at least one attempt by Rampage to take it back. Megatron eventually used the spark fragment to form the core of Dinobot 2, who likewise retained the ability to torture Rampage into continued loyalty with it (Apparently without any effect on himself).
Though a violent sociopath, Rampage was not without compassion. He found a kindred spirit in the badly damaged Transmutate and sought to protect it from the other Predacons. When Transmutate was killed, Rampage bellowed in grief.
Later, Depth Charge arrived on prehistoric Earth with the single-minded goal of destroying Rampage. Rampage was beside himself with joy, eager for revenge on his old "playmate",to the point of abandoning a planned attack on the Ark when he detected Depth Charge's arrival. Depth Charge's loss at Colony Omicron had embittered him, and Rampage used this emotional wound to torment the Maximal. They met in battle numerous times, fairly evenly matched.
While Megatron was retrieving the submerged Decepticon craft Nemesis, Depth Charge met Rampage in battle one last time. At the battle's climax, Rampage allowed Depth Charge to kill him with a shard of raw Energon, resulting in a fantastic explosion which destroyed both. Rampage won even in death, laughing maniacally in triumph as Depth Charge made the final, stabbing blow.