You send a ghostly soul into the target, dealing X Shadow damage and increasing all damage done by your damage-over-time effects on the target by 20% for 12 sec. When the Haunt spell ends or is dispelled, the soul returns to you, healing you for 100% of the damage it did to the target.
You send a ghostly soul into the target, dealing X Shadow damage and increasing all damage done by your damage-over-time effects on the target by 20% for 12 sec. When the Haunt spell ends or is dispelled, the soul returns to you, healing you for 100% of the damage it did to the target.
Haunt is a talentedwarlock ability that causes direct damage and places a debuff on the target, amplifying all Shadow-based DoTs cast on it. When the spell duration is over, it returns the amount of damage the Haunt spell itself caused (not the DoTs amplified, only the direct damage) as a heal.
When soloing, casting this spell on mobs tagged by other players grants you a quick and strong heal and gives them a hand killing the mobs. Everyone's happy this way!
This is a great spell for warlocks in arena. Aside from boosting a 'lock's DoTs, the heal it provides can occasionally save lives.
In PvE, this spell is to be kept up on a boss target at all times, significantly boosting the Affliction Warlock's overall single-target DPS. With the talent Everlasting Affliction, a well-timed spell rotation makes it so that one never needs to cast Corruption again after the first time.
Edit
Patch 3.1.0 (2009-04-14): Now only increases your shadow damage-over-time on the target. (No longer includes non-Shadow damage over time spells.) 
