DeepStar Six (released in the Philippines as Alien from the Deep) is a 1989 American science-fiction horror film directed and co-produced by Sean S. Cunningham.

Its plot follows the crew of the titular underwater military outpost, who struggle to defend their base against the attacks of a sea monster (possibly a giant eurypterid).

The film's cast includes Greg Evigan, Taurean Blacque, Nancy Everhard, Cindy Pickett, Miguel Ferrer, Nia Peeples, and Matt McCoy.

The project is headed by John Van Gelder, to test underwater colonization methods, while overseeing the installation of a new nuclear missile storage platform.

Already nearing his deadline, Van Gelder's plans are threatened when geologist Burciaga discovers a massive cavern system under the site.

Van Gelder orders the use of depth charges to collapse the cavern, to the dismay of Dr. Scarpelli, who wants to study the potentially primordial ecosystem inside.

Submarine "Sea Crab" pilots Osborne and Hodges send an unmanned probe to explore, but lose contact and venture in after it.

The aggressor then attacks the observation pod "Sea Star", leaving Joyce Collins and a dying Burciaga trapped inside as it teeters on the edge of the ravine.

Norris electrocutes herself and the Depladon as it attacks her, allowing Collins and McBride to escape, fleeing before the reactor goes critical and explodes DeepStar Six.

[5] Variety said the film was "diluted by implausibility" due to the monster's appearance being unrealistic rather than threatening, also criticizing the lack of centralized characters.