Like Fixit, Toolbox was one of many older-model Mini-Cons assigned to guard the Alchemor. He shares many things with Fixit and the multitude of other Mini-Cons station aboard the prison ship, right down to appearance, the sound of his vocal processor, and the multi-purpose tools and weaponry that aid him in ensuring the prisoners stay locked up.
Transformers Robots in Disguise
At one point, Toolbox received upgrades alongside Flowchart, Schematic, and Rundown.
When the back half of the Alchemor crashed in the waters outside Crown City, Toolbox was one of the many Mini-Cons aboard who were overpowered by escaped Decepticon prisoners and fitted with inhibitor collars, keeping them from being able to transform or access the weaponry needed to pacify the prisoners. After Scorponok, Glowstrike, and Saberhorn took over, he and his fellow Mini-Cons were put to work repairing the portion of the ship, so that the Decepticons aboard might use it to plunder the galaxy.
In Decepticon Island (Part 1), after a new Decepticon named Steeljaw arrived on the island, Toolbox heard tell of a group of Autobots on Earth. With the back half of the Alchemor's repairs nearly complete, Toolbox escaped "Decepticon Island", and found his way to Denny Clay's scrapyard, where he collapsed from weariness. After being given a buff and a tune up from Fixit, he regained his strength, and described what had happened to Fixit along with the other Autobots. Together with the Autobots, they devised a plan to infiltrate Decepticon Island and set of a bomb to cryo freeze the entirety of the Decepticons on the island all at once which Toolbox helped out in setting Grimlock ready. However, in the midst of their infiltration, another captured Mini-Con, Cinch, spotted Toolbox and called out to him, alerting the Decepticons to their presence. Soon, Toolbox and the Autobots were surrounded, and then "welcomed" by the island's new leader: Steeljaw, wielding a pair of Decepticon Hunters.
In Decepticon Island (Part 2), thankfully, Toolbox and the others were able to get away thanks to Windblade's quick thinking. Deciding to split up, Toolbox led Bumblebee and Optimus Prime to the ventilation system. However, Steeljaw anticipated their plan, and, having acquired Bumblebee's Decepticon Hunter, used them to power himself up to fight the two Autobots, while Toolbox looked on from a distance. As the battle continued, strongly in Steeljaw's favor, Toolbox called for help on an Autobot-only frequency. His pleas for help were met by his fellow Mini-Cons, whose collars had been disabled much like Toolbox's own. As the others opened fire on Steeljaw using their built-in weapons, Fixit goes to Toolbox upon telling him about receiving his message and prompted Toolbox to deploy his weapons as he joined in with the others in blasting Steeljaw. Though Steeljaw overwhelmed them, Optimus was able to prevent Steeljaw from attacking Bumblebee, who successfully started the stasis bomb. Once the bombs were ready, the Mini-Cons used their system probes on Steeljaw, forcing him to drop his Decepticon Hunters and lose his power up. Bumblebee dove for the weapons, and after powering himself up, easily dispatched Steeljaw, giving everyone enough time to escape the Alchemor before the bombs went off which all the Mini-Cons used their system probes to hitch a ride on Optimus and Bumblebee as they made their way safely back to the boat right after the stasis bomb went off.
With the Decepticons all back in stasis, Toolbox shakes Fixit's hand as a show of gratitude and he referred to Fixit as "cousin". All of the Mini-Cons, including Toolbox, elected to complete the Alchemor's repairs and return to Cybertron, taking with them the Decepticon prisoners, Optimus, Windblade, Ratchet, and Undertone, who had also joined the group for this mission.