The Hive Mind was created on Aegis 7 almost 200 years prior to the events of Dead Space, as a byproduct of the Red Marker. It is not entirely clear if it was created on purpose through the tests with the Red Marker, or if it was an accidental outcome of other testing going on. Either way, the secret government agency doing the tests deemed the creature too dangerous, and abandoned the project. The Red Marker had some sort of power over the Hive Mind, keeping it sealed under Aegis 7 until it was discovered during the mining operations just prior to Dead Space. Since it is ultimately the source of all Necromorphs, it serves as the final boss in the game. The planet Tau Volantis, as seen in the sequel Dead Space 3, was the home of an alien civilization that was in the final stages of being overwhelmed by a Necromorph infestation when its destruction came; at one point, a valley can be seen containing several fully-formed, albeit frozen solid, Hive Minds. One such Hive Mind, referred to by the researchers of Tau Volantis as a "Nexus", serves as a boss fight midway through the game.
The Hive Mind appears similar to the other Necromorphs encountered in the game, however unlike many of the individual Necromorphs, the Hive Mind is not re-animated human flesh. Like the other larger Necromorphs, such as the Leviathan and the Slug, the Hive Mind has many tentacles that it utilizes presumably for locomotion (it is seen pulling itself out a crater with these tentacles), and also to attack the player. Since it is only seen sticking its mouth and chest up from a crater, its exact size is unknown, however it is presumably larger than what the player sees during the final encounter. The Hive Mind has the characteristic weak spot of some of the other Necromorphs; the large yellowish balls of flesh that the player must shoot. There are 5 of these sacs of flesh around what presumably is the creature's head, and 5 more behind a protective wall of bones, which open when the creature is at rest, allowing Isaac to shoot them. This second set of sacs are hypothesized to be the creature's hearts.