Betabear

Betabear is a pre-faction gladiator from the Generation 1 continuity family.

You can't see me!

_{This character has no official visual representation in any Transformers product or media... yet, at least.}

Betabear was a gladiator during Clench's days as team captain.

Fiction

IDW comics continuity

During a team vs team match, Betabear failed to act on Clench's order to get in circle formation and was killed off by one of the other team. Megatron Origin issue 2