From Elemental Lords of Porphyra

Slippery Crown
Aura moderate illusion/ conjuration (teleportation); CL 7th; Weight 2 lbs
Slot head; Price 26,400 gp
Description
This bizarre-looking piece of metal headgear is intended for those who expect betrayal and/or disaster to strike at any moment. Once per day the slippery crown can be activated, so that within the next hour, if the wearer takes damage from a physical or magical attack, or is affected by a magical attack that requires a saving throw, the wearer will be automatically affected by a dimension door effect, teleporting the wearer up to 600 ft. away. In the wearer’s place, a simple illusion of the wearer will be created, that will repeat the action of the wearer in the previous round, until dispelled or disbelieved.
Construction
Requirements Craft Wondrous Item, dimension door, major image; Cost 13,200 gp