The Fastest Bot Alive! is the thirteen episode of Season 3 and the fifty-eight overall of Transformers: Robots in Disguise.
Grimlock acquires uncontrollable superspeed, which proves to be a problem when the Autobots have to deal with a revenge-minded Simacore and his army of Mini-Con clones.
Grimlock hurries through the scrapyard, and is passed by Sideswipe. When he asks Sideswipe to wait up, his fellow Autobot berates him for being slow and rushes off. Grimlock reaches the control center to find the rest of the team lying groaning on the ground, and Fixit advancing on him with a sharp tool. Though Grimlock suspects some sort of mind control, Bumblebee reveals Fixit's taking particle samples for his combiner research. Grimlock reluctantly consents. With the samples analyzed, Fixit calls for volunteers for a combiner test. No one is keen to take part, so Bumblebee volunteers himself and Strongarm. The experiment successfully merges the two Autobots to "Bumblearm", however Strongarm in leg mode seems to be unable to move, and Fixit asks Grimlock to carry the combined Bots to his lab table. When Grimlock attempts to get up, he flies off into the air at super speed. The rest of the team finds him in a pile of wrecked junk, and moments later he again flies off in another direction. The combiner effect has now worn off, so Fixit, Bumblebee and Strongarm catch up with the others, and Fixit theorizes that the extractor wasn't calibrated for Dinobots and somehow turbo charged him. Grimlock is overjoyed at the news and knocks Sideswipe flying. The others break it to Grimlock that he'll have to stay put, as his superspeed is too dangerous. Fixit's tracker alerts the Autobots to multiple Decepticon signals under Crown City. The others head off to the GroundBridge, but Grimlock's left behind. Russell attempts to cheer him up by reading him the latest Captain Plasma Beam comic.
Bumblebee, Strongarm, Sideswipe and Drift end up at an abandoned subway entrance, where they find the tunnel has been sealed off with subway cars.
Back at base, Grimlock decides what he needs is training in his powers. Despite flying up into the air, he manages to stand up. Russell protests, but Grimlock somehow succeeds in running between a row of gas pumps without hitting any of them — just everything else in the area.
The rest of the team starts moving into the subway tunnel, onto to be set upon by a horde of monkey Mini-Cons. They realize the Mini-Cons look like mini-versions of Simacore, and Drift pegs them as sparkless clones, however the Autobots soon discover there are enough of the Mini-Cons to cause them a problem.
At base, Grimlock has made himself a superhero costume. Fixit gets a comm from Bumblebee, but has to admit that Grimlock's speed hasn't worn off. Grimlock is super-confident that he's ready, despite Denny and Russell's disagreement, and rushes through the GroundBridge when Fixit opens it in case the rest of the team needs to withdraw. Arriving at the subway station, Grimlock manages to take out all the miniclones. Bumblebee is disappointed that Grimlock didn't stay at the scrapyard, but when he announces they need to find the source of the Mini-Cons, Grimlock immediately runs into the tunnel and crashes. The rest of the team follows and finds him having slammed into a wall. The other Autobots load the apologetic Grimlock onto a rail car so they can push him along a track, and eventually find a side corridor, though they're forced to leave Grimlock on the tracks as they go in. At the end, they find Vertebreak's old lab which seems to again be in use as a cloning facility. The four Autobots are unexpectedly hit by arcs of electricity, paralyzing them just before Simacore himself turns up. He explains his stasis pod was faulty and he escaped.
Hearing Grimlock, he heads down the corridor to attack the Dinobot, only to be met at super-speed by Grimlock coming the other way. Despite having been slammed into a wall, the Decepticon is still functional, and Grimlock is afraid to move again, forcing him to allow Simacore to throw him around. Once Simacore reveals that Grimlock is his arch enemy, Grimlock realizes he has become a superhero, and Bumblebee manages to pep talk him into taking action. Grimlock whacks the Decepticon, knocking him into the energy arcs. Simacore is knocked out, and the other Autobots are released. Bee asks Strongarm to contact the human authorities about the area, once the Cybertronian tech has been cleared out.
The team carries Grimlock back through the GroundBridge to the scrapyard, where Fixit announces Grimlock's superspeed is already starting to wear off. Grimlock's happy to be on the way back to being slow again, and Denny and Russell break out an industrial-sized roll of bubble wrap.
"You must have me confused with that mild mannered and handsome Dinobot, Grimlock. I'm Grimlock, equally good looking and handsome and heroic superhero. Hang on, the wind's picking up." [poses heroically as his cape flaps]
"Shhh! Don't give away my secret identity! I'm supposed to be incognemo."
- —Bumblebee is annoyed Grimlock left the scrapyard.
"You are my greatest foe!"
"You mean, kinda like your arch enemy? I did become a superhero!"
- —Simacore accidentally makes Grimlock's day.
"You never know how big a Dinobot is, until you have to carry them."
- Simacore and his Mini-Cons, Axiom and Theorem, were out-witted by Grimlock and captured in "Brainpower", and were supposed to be taken back to Cybertron by Optimus Prime when he departed with the Alchemor at the end of "Decepticon Island (Part 2)". As Simacore claims his stasis pod failed "long before" that happened, it's clear somebodyforgot to take a head-count.
- Grimlock wonders if Fixit has been taken over by "a Decepticon like Minitron", a Cyber-tick who took him over in "True Colors".
- Fixit's research into controllably forming Ultra Bee has been taking place off and on since the Bee Team gained the combining ability in "King of the Hill (Part 2)"; while he managed to briefly combine Sideswipe and Grimlock in "Out of the Shadows", Bumblearm is the first (mostly) successful combination to result, and the first to actually receive an on-screen name.
- Russell tries to remind Grimlock that skill takes time to develop by recalling his field goal kicking practice, as seen in "King of the Hill (Part 1)".
- Simacore's cloning facility uses Vertebreak's lab from "Some Body, Any Body".
- In stasis: Crustacion, Ragebyte, Zorillor, Springload, Boostwing, Jacknab, Pilfer, Shadow Raker, Flamesnort, Simacore
- Bumblebee's "holy hurricane mode" comment appears to be a reference to the "hurricane mode" which Landfill in the RID anime takes on when that version's Grimlock forms his arms.
- The episode's name references the tagline of The Flash, "The Fastest Man Alive".
- This is the second time Grimlock has worn a cape. The first time was in "Suspended".