Phantom Zoners

Phantom Zoners are criminals from the planet Krypton. Having been charged with various crimes, they are sentenced into exile in a place called the Phantom Zone, which is an interdimensional pocket of space.

In the original Superman film series, the characters of General Zod, Ursa, and Non were charged with acts of seditious treason. They were teleported into this two-dimensional plane of reality represented by a pyramid-shaped window that floated through space. This window was the criminals' only means of seeing beyond their own environs. Fortunately for them, a shock wave from a space-borne hydrogen bomb shattered the Phantom Zone barrier and they escaped.

In the DC Extended Universe, there were several more Kryptonians who were transported into the Phantom Zone. These were all soldiers who were followers of Zod, who rebelled against the reigning Kryptonian Council for refusing to do anything about the planet's pending destruction. These beings were exiled into the Phantom Zone, which turned out to be the best thing for them, as they had survived the destruction of their homeworld. They too eventually escaped and came to Earth seeking to terraform it, transforming it into a world ideal for reconstituting the Kryptonian race. Their efforts brought them into conflict with another Kryptonian, Kal-El. Through the course of an epic battle in the city of Metropolis, all of the Phantom Zone criminals were killed.