Sludge

Sludge is the second of the three original Dinobots, built on Earth alongside Grimlock and Slag after the Autobots found dinosaur bones in their volcanic headquarters. Wheeljack and Ratchet gave the Autobots the raw firepower they lacked, and immediately handed them a discipline problem. Optimus Prime judged the prototypes too dangerous and ordered the project abandoned; Wheeljack kept working in secret on memory components that would make them smarter and more controllable, and when the Autobots were captured at the Great Falls hydroelectric plant, it was Sludge and his two teammates who forced the Decepticons to retreat and earned the Dinobots a place on the roster.

Even by Dinobot standards Sludge is slow. Grimlock's own summary is "Sludge dumb", and the Dinobots' reputation for being dim is arguably undeserved by everyone except him. Unable to make an impression mentally, he makes one physically, stomping his considerable bulk around so that everybody knows he is there. He is also, unexpectedly, one of the nicer ones. He believes in the Autobot cause; his objection to Optimus Prime is philosophical in a very Sludge way, since he holds that the strongest should lead and in his estimation Grimlock is the strongest Autobot alive. He tolerates Prime rather than following him.

That tolerance ran out in "Desertion of the Dinobots", when the Dinobots abandoned an Autobot force dying for lack of Cybertonium and headed for Cybertron, where Shockwave captured and reprogrammed them into mine labour. Earlier, in "War of the Dinobots", Megatron had talked him and the other originals into defecting outright, forcing the Autobots to build Snarl and Swoop to stop them. Sludge always came back, but only ever behind Grimlock.

Sludge transforms into a robotic brontosaurus whose sheer mass is the weapon: he stomps, crushes and creates ground tremors, and in robot mode carries an energo-sword, an electron cannon and a three-shot rocket pod. Against a fixed target or a Decepticon who cannot get out of the way he is devastating. Everything else is a weakness. He is the least intelligent of the Dinobots by a wide margin, which is a real tactical vulnerability rather than a joke: Megatron manipulated him into changing sides in "War of the Dinobots", and Shockwave reprogrammed him wholesale on Cybertron. He is ponderously slow, a huge target, and easily swayed by anyone who tells him what he wants to hear. In the 1986 movie Devastator hit him so hard his optic sensors bulged out of his head.

• Grimlock: his measure of everything, since Sludge holds that the strongest should lead and Grimlock is the strongest.
• Optimus Prime: tolerated rather than followed, because Sludge believes in the Autobot cause even though he does not accept Prime's right to command.
• Wheeljack and Ratchet: his builders, with Wheeljack the one who kept refining his memory circuits after Prime shut the project down.
• Snarl: his most frequent partner in the later cartoon, the two of them left behind on guard duty together in "Dark Awakening".

Marvel scraps the fossil-inspired Earth construction entirely. Sludge was one of the Ark's original crew; when the Ark detected Shockwave in the Savage Land it used data gathered there to convert five dormant Autobots into Dinobots and sent them to fight him. The fight ended with every combatant trapped in a tar pit, where they stayed for millions of years until Ratchet freed them in "Repeat Performance!" and they helped him defeat Megatron. Four million years in tar had eroded the insulation on their primary cybo-dendrons, and Sludge burned out and reverted to base instinct, ending up in the waterways of Littlewood, California during "Dinobot Hunt!". There he was befriended by a human journalist, Joy Meadows, and Marvel then does something the cartoon would never attempt: it gives Sludge an open, unrequited crush on her, which both Joy and his own teammates find deeply strange, and which drives the plot of "In the National Interest" when Triple-I marks her for death and Sludge saves her life. Marvel's Dinobots also speak in full sentences and, under Grimlock, briefly take over the Autobots outright.

Sludge survives G1. He fights Devastator at the Battle of Autobot City in the 1986 movie, is stranded on Quintessa with Hot Rod and Kup, and remains part of the Dinobot unit on Cybertron through season three, appearing in "Grimlock's New Brain", "Call of the Primitives" and "Dark Awakening", with later appearances in the Japanese Headmasters series. In Marvel continuity he is destroyed by the Underbase-powered Starscream, revived with Nucleon by Grimlock, killed again fighting Unicron, and finally resurrected by the Last Autobot.

• The toy is a repurposed Diaclone Dinosaur Robo Brontosaurus. The only differences from the Diaclone release are a gold-chromed sword and the red-and-black pilot figure that came with it; the driver compartment is still visible in his chest.
• Sludge is the only one of the five original Dinobots whose alt mode is not shared with another Transformers character, helped considerably by the fact that the brontosaurus was a skeletal misidentification and never existed as a distinct species.
• He has effectively no dialogue in The Transformers: The Movie. His one line, "Quiet!", is delivered in Grimlock's voice, and his name does not appear in the end credits at all.
• Frank Welker voiced him in the US cartoon and Kenyu Horiuchi in Japan.
• Sludge and Swoop were both absent from the Generation 2 toy line for reasons never explained, though unearthed packaging art of both in new colour schemes, alongside a yellow-and-turquoise Grimlock, suggests a second Dinobot wave was at least considered.

Where the cartoon, the Marvel comics and the toy bios disagree, or where a popular claim does not hold up. We record these rather than smoothing them over.

• Origin: Earth-built from fossils by Wheeljack and Ratchet in the cartoon versus reformatted Ark crew sent against Shockwave in the Savage Land in Marvel.
• Intelligence: Grimlock's "Sludge dumb" assessment and the cartoon's portrayal sit awkwardly against Marvel's articulate, emotionally complex Sludge who conducts a one-sided romance with a human reporter.
• Loyalty: the cartoon has him accept the Autobot cause while rejecting Prime's authority; Marvel's Dinobots repeatedly break away from Autobot command entirely and serve under Grimlock as a rival leader.