"Place a rune of protection on yourself for 1 minute. The next enemy to attack you is imprisoned in a sphere of dark magic, disorienting them for 16.6 seconds. The disorient is broken if the enemy takes direct damage. You can only have one Defensive Rune at a time. You cast the spell on yourself, disorienting the next enemy who attacks you."
―Skill description

Defensive Rune is a morph of the Sorcerer Rune Prison ability in the Dark Magic skill line in The Elder Scrolls Online.