Undertow (G1)

Undertow is an Autobot from the IDW portion of the Generation 1 continuity family.

Nautilus... is that you?

Undertow is one of several Autobots in Optimus Prime's lineup of young, inexperienced new Autobots. He seems to be designed to transform into some sort of underwater vessel or submarine.

Fiction

IDW comics continuity

In the early years of the war, Optimus Prime decided that he needed to have a parade line-up and inspect the brand new Autobot troops! Ironhide thought this was a stupid idea and told Prime so. Undertow just happened to be one of the members of this brand new lineup of dudes. He was standing between Tracks and Brainstorm. All Hail Megatron issue 13