Mist Form

Description
For 8...18 seconds, you cannot take or deal damage from attacks. This is an elite skill.

Technically, you can not be hurt by warriors in PvP for the duration when you have Mist Form on, this is because warriors use swords, hammers, and axes. Since you're a mesmer and you use spells, Mist Form doesn't apply and because warriors use weapons and not spells to attack, you have a great advantage.

Acquisition

 * Iron Mines of Moladune (Mission): Eidolon
 * Mineral Springs: Ice Beast (Eidolon)
 * Ring of Fire (Mission): Eidolon
 * Snake Dance: Sala Chillbringer (Azure Shadow)
 * Talus Chute: Brrrr Windburn (Azure Shadow)