Bad Spark is the thirty-fourth episode of the Beast Wars TV series.
Cheetor, on recon patrol, spots a giant stasis pod (labeled with a big yellow "X") crashed inside a patch of unstable energon deep inside a murky swamp. Optimus Primal orders Cheetor not to open the pod until he arrives. As Optimus and Silverbolt leave, Rhinox invokes the help of Primus if "that thing survived". However, the Predacons intercept the transmission, and Megatron sends Blackarachnia and Waspinator to retrieve it, subtly planting a listening device on the former. He calmly taps his chair armrest, possibly aware that Tarantulas left a bug of his own under it.
When Optimus and Silverbolt meet Cheetor beside the pod, they find the protoform within apparently dead, and Primal seems relieved. When the other two ask why, Primal tells them what the pod means: The stasis pod holds "the dark secret of Axalon's journey," Protoform X. Protoform X was created in experiments attempting to replicate the mutation in the spark of Starscream, making it indestructible, but the subject was treacherous and insane, so the Axalon was to dump the protoform "somewhere far, someplace barren."
Blackarachnia and Waspinator strike, attempting to take Protoform X for themselves. Attacking Silverbolt, Blackarachnia is angry that his code of honor won't allow him to fight back by hitting a female. Then Tarantulas arrives and threatens her. Silverbolt defends her, but the battle accidentally ignites the energon beneath Protoform X's stasis pod, which explodes and triggers an energon storm that scatters everyone for miles.
Blackarachnia and Silverbolt crash-land next to each other. They agree to work together, as they are far from their respective teams and Silverbolt's wing is broken. Tarantulas lands next to the pod; he investigates it, only to find it empty. He then turns to find something looming over him through the mist. His scream echoes for miles...
Optimus Primal and Cheetor return to the Axalon, too damaged to search for Silverbolt. Blackarachnia and Silverbolt journey by foot, learning to trust each other, but Megatron is eavesdropping on them. They soon discover a piece of Tarantulas and conclude with dark humor that he is no longer a threat. Inferno is disgusted by their alliance, but Megatron notes that with Tarantulas out of the way, Blackarachnia no longer needs a protector. This becomes apparent when Silverbolt is the first to cross a log bridge, only for Blackarachnia to pull her weapon on him. However, a saber-toothed cat attacks her, which Silverbolt defeats, but is left dangling on a vine. Blackarachnia saves Silverbolt, awkwardly saying that it was in case there were more tigers around. Megatron is disgusted, as it is apparent that she may have feelings for the Maximal.
As the two Transformers walk on, Silverbolt tries to appeal to Blackarachnia's "inner Maximal goodness", only to receive gunfire in return. As Blackarachnia stomps off, she finds Tarantulas's stasis locked body—in several pieces. Silverbolt notes that Protoform X must have done this, and tells Blackarachnia about the protoform's indestructible spark. Megatron, still eavesdropping, fashions an energon blade in preparation. Blackarachnia, freaked, prepares to high-tail it out of the area as an ominous form skitters through the fog behind them. Suddenly, the two find themselves face-to-face with Protoform X! Huge and frightening, it knocks them around effortlessly and is immune to their firepower. The monster lifts Silverbolt in its powerful claw, relishing his victim's mounting terror. Silverbolt screams in pain as X crushes him.
Primal and Cheetor arrive in the nick of time and attack, freeing Silverbolt. Blackarachnia joins them in blasting Protoform X, eventually driving it off a cliff edge. However, it transforms into tank mode and ascends the cliffside. Silverbolt throws a feather missile, knocking him down into another pile of raw energon, but not before Protoform X fires at Blackarachnia, knocking her off the other side of the cliff. Silverbolt jumps after her, unsure if his wing mechanism is healed, but he succeeds, and she is saved. The Maximals let her go before returning home. Blackarachnia watches them depart, then uses her grappling wire to depart, emphasizing a claim that she didn't need Silverbolt's last rescue.
Helpless in the pile of raw energon, Protoform X sees Megatron appear over him with the energon blade. X wakes up in the Predacon base to find that Megatron has carved out a piece of his spark and put it in a tiny cage that, when squeezed, causes him tremendous pain. Megatron has Protoform X at his mercy and renames him "Rampage".