The 8th level Revenant Domain spell is a counterpart to the 6th level Hallucinatory Domain spell, with an important difference: the domain can go through active and inactive cycles, depending on the presence or absence of a caretaker. When a sentient being enters the physical boundaries of the domain, the victim must make a saving throw; failure means that the being is ensnared by the illusion as it re-activates. If the victim breaks free and there are no other sentient beings that the spell can affect (or all potential victims make a saving throw,) the domain returns to dormancy; illusory towers topple, walls crumble, vegetation turns to dust. The enchantment lies in wait for its next victim.
The 9th level Revenant Universe is the astral equivalent. A small target area in the physical world becomes a trap, requiring a saving throw for any sentient being that crosses the boundary; those that fail the save vanish astrally into the depths of space and the hallucinatory universe defined by the spell re-awakens. Effectively, the target area becomes a one-way "dimensional gate".