Response to Lord Kynd.
Nope, you're thinking of Cloak of Corruption. The Cloak of Corruption does this.
"Cloak of Corruption Abilities:
Attempts to aggro a large area around the player
* Doesn’t work in towns/guard zones
* Cannot aggro players, pets, summons, or benign creatures
* Cannot aggro anything that is currently in battle
* Increases speed of aggro’d mob for several minutes
* Boosts Fame obtained from aggro’d mobs
* Can draw attacks up to 30 tiles away
Rapidly decays Karma
* -500 karma every 30 seconds equipped
Rapidly decays HP, Mana, Stamina in the normal world
Rapidly restores HP, Mana, Stamina in the Ethereal Void
To sum: A dread's best friend, or a hero's shield in the unknown"
Funny how what the Vanguard's wear is called the "Cloak of Shadows" when the actual Cloak of Shadows was an Ethereal looking Cloak that was looted off of Lady Morwenna on Napa. What the Vanguards wear is like the "Hooded Shroud of Shadows".