The Slug Sub is an underwater vehicle used by the Regular Army.
The Slug Sub is a small submarine used during the Second Mission. Unlike other slugs, it doesn't have a Vulcan equipped on it, rather relying on torpedoes. When it's resurfaced, the Slug Sub can fire homing rockets, which get replaced for depth charges when it submerges.
- The Slug Sub was most likely based on the Granvia from In The Hunt, as both submarines play very similarly.