The Deep One is a horrific alien bioweapon created from the insidious experiments of the Aquatoids. It is a hybrid of Human and Aquatoid, though all human characteristics except for its eyes have been lost. It accompanies the Gillmen on Terror Missions.
Deep Ones are created by a nightmarish transformation that turns it from a simple human into an assassin of the alien menace. A parasitic Aquatoid-derived fetus is implanted into the host, which then proceeds to consume it and ultimately fuse with it. After the transformation is complete, the newborn Deep One is fitted with a visor and breathing tube, and has an Aqua Plastic mesh grafted onto its skin a la the Mutons. Thousands of these creatures are manufactured by the aliens to extend their mighty army.
Deep Ones have many Aquatoid traits, including green skin, webbed hands and feet and a bulbous head with a line of bony protrusions on its forehead. The Deep One is slightly taller than the Aquatoid, and is easily recognized by its breathing mask and black visor with two glowing red eyes behind it.
The Deep One prefers to stay out of firefights, hiding away in secluded corners or behind obstacles. When a target wanders too close, it quickly attacks with a barrage of lethal electric shots that ignore armor and can kill an Aquanaut in several well-placed shots. It is resistant to most Armor Piercing attacks, but Gauss and Sonic weapons can fell them easily.
A Deep One Corpse must be researched in order to research Aqua Plastic. Researching a live Deep One is needed to research Ion Armor.