Tankor is a Vehicon and a villain in the Beast Machines series, the sequel to Beast Wars.
Megatron found the Maxies are playing with the big boys now! After Megatron claimed there were fabulous prizes to be won, for whichever general got the Maximals, Tankor went after them and, after a vicious battle, actually captured them. He then took them to Megatron and demanded his reward which managed to use his affinity with the Allspark to contact Tankor's spark and convince him to do the right thing: the Vehicon helped them escape and went on the run with then, but Megatron was able to remote delete the tank's memories of this so he'd be their enemy again. Primal felt something familiar about that spark though. The Maximals tried to ambush Tankor to see whether drones would stop functioning without their general; the plan would go tits up, however.
Tankor found the Oracle and, using his escalating arms race gambit worked in manipulating Megatron into firing the key on a planetary scale which would have killed all the organics, when he tried to attack Megatron, and a provision against doing so, hard-wired into his programming, shut him down. Due to Tankor's manipulations, however, Primal opened the Plasma Energy Chamber and Megatron fired the Key. The ensuing clash of energies destroyed Tankor's body, and his spark joined the Matrix. Primal met Rhinox's spark one last time within the Matrix, where Rhinox expressed regret over his recent actions.
In the video game, Super Smash Bros. for Nintendo 3DS / Wii U, one of R.O.B.'s alternate costumes is based on Tankor's color scheme.