A sturdy, well-rounded ranged slug stuffed into an augmented diving suit with a powerful self-defense mechanism.
Aquanauts are an intelligent race of gastropods, friendly with the Nautilusks, that were culled into endangerment by the savage ocean wildlife. Timely luck struck their race as a massive frigate crashed into the ocean. Hundreds of augmented and weaponized diving suits contained in its armory were discovered and repurposed. The Aquanauts, despite finding the suits to be a tight fit, became able to defend themselves with technology ahead of their time.