The Nexus (star trek)

The Nexus is a spatial anomaly that exists in the fictional universe of Star Trek. It is a ribbon-like energy pattern that travels through space. When it comes into contact with sentient life forms they are turned into part of the energy pattern. There they exist in a dream-state where eternal happiness is achieved by the crafting of an ideal universe. It is very difficult to "snap out" of the false reality and return to one's original physical life once becoming one with The Nexus.

Captain Jean-Luc Picard merged with The Nexus briefly, and rescued Captain James T. Kirk from within.