Shadow Door

By means of this spell, the wizard creates the illusion of a door. The illusion also permits the wizard to appear to step through this "door" and disappear. In reality he has darted aside and can flee, totally invisible, for the spell duration. Creatures viewing this are deluded into seeing or entering an empty 10' x 10' room if they open the "door." A true seeing spell, a gem of seeing. or similar magical means can discover the wizard. Certain high Hit Dice monsters might also notice the wizard (see the Invisibility spell), but only if making an active attempt to do so.

[Player's Handbook]

School: Illusion/Phantasm
Level: 5
Rarity: Common

Range: 10 yards
Components: S
Duration: 1 round/level
Casting Time: 2
Area of Effect: Special
Saving Throw: None