Supreme Commander FA: Below The Surface

Cybran Plan B T3 Strategic Missile Sub. Since Cybran Nation tends to create units with additional roles, this sub carries torpedoes in addition to Loa Tactical Missiles, and also becomes useful in ship-to-ship combat. In addition, Loa Tactical Missiles (not only on this sub, but also on mobile and stationary ground-based launchers) split into submunitions when hit by tactical missile defense.
And, as any other human factions' T3 SMS, it can build and launch nuclear missiles. It also has a darkly humorous class name.