Sphere

The Sphere is an unknown object of extraterrestrial origin found in an American spaceship from 350 years into the future. It's purpose, origin or anything else about it remain a complete mystery to everyone, in-universe and out.

Biology
It's not clear if the sphere is alive or not, making its status as a living creature somewhat dubious at best. However, it can be opened, assuming you believe it can be opened. For reasons that cannot be explained, anyone who enters the sphere gains the power to warp reality, manifesting their own imaginations however they may choose.

History
Some point in the future, an American spaceship goes on an expedition across space, collecting various alien artifacts wherever it goes. The sphere is the most prominent thing they discover, and kept in the ship's cargo hold. Somehow, the ship gets sucked into a wormhole, ending up hundreds of years in the past. Eventually, the ship is discovered by the U.S. Navy at the bottom of the Pacific Ocean. A group of scientists attempt to explore the futuristic spacecraft, eventually happening upon the sphere itself. They continue to speculate the purpose of the sphere, ultimately achieving nothing beyond theories and guesswork. Three of the personal - Harry Addams, Elizabeth Halpern and Norman Johnson - enter the sphere itself, developing the ability to manifest their imaginations. Before any of them realize this, their fears begin to manifest themselves uncontrollably, creating creatures such as jellyfish and squid, each of which should not exist in nature. Eventually, the facility is destroyed, the sphere lost to the bottom of the ocean, and the survivors choose to use their powers to forget everything they witnessed. However, it's heavily implied that Elizabeth Halpern chose to keep her reality-warping powers.

Appearances

 * Sphere (1987)
 * Sphere (1998)