Marvel Comics continuity
In a plot to steal energy from Hoover Dam, Megatron ordered Bombshell to implant a cerebro-shell in the brain of Ricky Vasquez, a worker at the dam. Bombshell showed Megatron the power of his shells by ordering the human to lick dirt off his foot, and Megatron and the Insecticons had a jolly good time when Vasquez complied. Their plan proceeded smoothly until the Aerialbots attacked, and Vasquez managed to overcome the cerebro-shell by focusing on his daughter. While the plan was foiled, Bombshell attached himself to Silverbolt and got into the Ark undetected, where he implanted another cerebro-shell into an open wound on Optimus Prime. While this shell failed to take control of the Autobot leader, it let Soundwave and Megatron tap into his thoughts, alongside the power of the Creation Matrix, which Megatron used to give life to the Stunticons.
Wheeljack later removed the cerebro-shell from Optimus Prime's skull and modified it to let the Autobots listen in on the Decepticons' plans instead. This led to Optimus Prime and the Protectobots going off to stop Megatron and his Combaticons from stealing the human hydrothermocline device.
When Bombshell and Dirge were ordered to take control of Power Station Alpha, they discovered Bumblebee watching it on behalf of the Autobots. To distract him, Bombshell fired a cerebro-shell into young Tony Duranti and ordered him to stand in front of the station's tracks during launch. Bumblebee was forced to transform and rescue him, which led to him being shot and killed by G.I. Joe for being a giant robot. Bombshell then infiltrated Power Station Alpha and planted a special cerebro-shell in its mainframe, which let Shockwave control it back to the Decepticon base. However, Doctor Mindbender of Cobra managed to lock onto the shell's electronic frequency and control the station over to the Cobra base instead. Meanwhile, Tony Duranti, whom Bombshell apparently forgot about after he served his purpose, had become completely unresponsive, so his mother took him to Doctor McGrath, who spotted the cerebro-shell via x-ray.
The shell was surgically removed and Duranti returned to normal, while McGrath started prodding the shell while trying to figure out exactly what it was. This caused Bombshell to spasm and transform out of his own control, although he only suspected some generic circuit malfunctions. Mainframe of G.I. Joe, whom also started prodding it. The deactivated Bombshell, who'd been brought into the very same room as the shell by Doctor Mindbender, started spasming again, and everyone found this very interesting.The shell eventually ended up in the hands of
In an attempt to ruin the Autobots' reputation amongst humans, Bombshell later injected Superion with a cerebro-shell, forcing the massive combiner to rampage through New York City. However, the Autobots recruited a reporter by the name of Irwin Spoon to climb inside Superion and remove the shell. Unfortunately, Irwin never got a chance to share this experience with the world, as Bombshell simply injected him with another cerebro-shell and made him write mudslinging stories about the Autobots instead.
Bug Bite reversed-engineered cerebro-shell technology in order to control the minds of his fellow Decepticons and take leadership of them. This worked out great until the signals from the shells were jammed by Autobots, and Bug Bite was killed by Megatron, who was immune to cerebro-shells anyway. A noteworthy innovation from Bug Bite's variation on the technology was that he modified his cerebro-shells to fit into the standard bore of Decepticon weaponry, presumably breaking the monopoly Bombshell had upon his signature weapon.
After being caught in a battle of misunderstanding between the Insecticons and the other Decepticons, Mirage was left sitting unconscious in a wasteland, where the Insecticons found him. Bombshell implanted a cerebro-shell in him, effectively turning Mirage into a slave to use against Megatron's Decepticons (whom the Insecticons considered enemies at the time, due to the aforementioned misunderstanding). When the two groups settled their differences, Megatron used Mirage to lead the Autobots into a trap. Cliffjumper punched the traitor's lights out in the ensuing battle, and Ratchet found and removed the cerebro-shell when examining him afterwards.
The Insecticons later devoured the Nova Power Core, which greatly increased their size and power. They decided that with this power, they didn't need to remain with Megatron anymore, and when Soundwave overheard their conversation, he was spotted and injected with a cerebro-shell. The Insecticons still followed Megatron to Iron Mountain, where they revealed the next part of their plan and fired cerebro-shells at Megatron and the Seekers. The latter group fell victim to Bombshell, but Megatron managed to grab and crush the shell fired at him. When Shrapnel later exploded, all the cerebro-shells were deactivated. Bombshell then used a "special" cerebro-shell to re-assemble his comrade.
Starscream's Decepticon faction used modified cerebro-shell technology to control humans working on the Binaltech project, in order to implant Decepticon personality components into the new bodies created for various Autobots.
Find Your Fate Junior
In the Dinobots Strike Back multipath adventure, the Dinobots (except Swoop) were injected with cerebro-shells, causing them to go on a rampage. Once rescued, Grimlock remembered that he could hear Bombshell's thoughts while under his control. This led to the Autobots uncovering the Decepticons' plans for Dolphin Bay.
Dreamwave comics continuity
Under the orders of Shockwave, Bombshell used cerebro-shells to make a human army out of the entire population of San Desto, California. During a confrontation with the Autobots, Bombshell himself had one of the shells planted on him, which caused a strange feedback loop and put him into stasis.
IDW comics continuity
Bombshell, by order of Soundwave, injected a cerebro-shell into Beachcomber in an effort to make him assassinate Blaster, the inspirational broadcaster for the Autobots. Beachcomber eventually managed to fight it and override the control mechanism, but the effort burned out a large portion of his neo-cortex.