DOUWD

The Douwd are a peaceful immortal extragalactic uncorporeal species, self-described as "beings of disguises and false surroundings". Through their uncanny psychic powers, they have the ability to create and destroy on an interstellar scale and maybe more. Although they can't bring people back to life, they can make illusionary recreations of them. Although seamingly nearly omnipotent, they are not omniscient.

One Douwd has been known to travel the Milky Way,sometimes under the form of a human in the course of the 24th century. During that time, he destroyesd the Husnock civilisation after they had wiped out a human colony on which he was living.

Source: Star Trek universe, (TNG: "The Survivors")