Beast Wars: Transformers S03E01 - Optimal Situation

As the Maximals begin to fade from the time stream, Blackarachnia switches sides and saves Optimus Prime with a life-support machine. The time storm fades, but Prime is still in danger so Optimus Primal takes Prime's spark into his body to stabilize it until Prime's body is repaired. The energy from Prime's spark causes Primal's body to mutate into a new "Optimal Optimus" form. Meanwhile, Rampage destroys the Axalon's supports, causing it to fall into the water below. Optimus later returns his ancestor's spark to his body after the repairs are done. Realizing that Megatron will continue to target the Ark, the Maximals gather what they can salvage from the Axalon's wreckage and begin turning the volcano around the Ark into a new base.