This is the ability to open doors to alternate planes of existence. The mutation manifests itself as a 3 x 3 meter opening lasting up to 3 full melee turns at the discretion of the mutant. These planes of existence may or may not be populated (with referee-inspired creatures), but once entered, there is no way to leave them (unless the mutant re-opens the door), so they make perfect places of exile. Only one such door may be opened per week.
This mutation offers a lot of opportunity for gaming groups to have cross-campaign adventures.