How about...
Illusions of Alamaranth (illusion, psionic) - Immediate interrupt
Trigger: a creature enters the Shrine of Laeris
Target: the triggering creature
Attack: vs Will
Hit: the target sees visions of the destruction of Alamaranth instead of the real Shrine. It treats the Shrine as difficult terrain and the Far Weaver has concealment against the target.
Miss: the target sees the Shrine as it truly is, with the destruction of Alamaranth as a transparent overlay.