Corborus

Corborus is the first boss of the Stonecore.

Adventure Guide
''Deathwing enslaved the massive gyreworm Corborus and drove it to unearth the vast amounts of elementium required to forge the Dragon Aspect's new plating. With Deathwing's departure, however, Corborus has broken loose and now rampages though the Stonecore in blind fury.''

Phase 1
In phase 1, Corborus will be on the surface. Positioning is not overly important, although ranged dps and the healer should not stack due to Crystal Barrage. When he casts Crystal Barrage, the affected player should move out of the crystals on the floor to avoid additional damage. Even though this can be healed through, with the limited mana of healers it is a good idea to avoid as much damage as possible. Corborus will also cast Dampening Wave which will cause damage and apply a stacking debuff to all players within 60 yards absorbing up to 4000 healing and can stack up to 20 times. This will need to be healed through or a single dispell will remove the effect.

Phase 2
Corborus will burrow underground in phase 2, in this phase he will summon small adds which deal minor damage. These should be taken care of throughout the phase and have a rather small health pool. As well as this, while burrowing, Corborus will cause clouds of dust on the ground. Players must stay out of these as he will periodically resurface and cause damage and a knockback to any players in the dust cloud.

He will resurface and go back to phase 1.

Heroic Difficulty
In phase 1 Corborus' Crystal Barrage will summon 8-10 Crystal Shards about 2 seconds after the effect finishes. These have 7.5k health and will move to the closest player. If they reach their target they will explode causing 20k damage and applying a debuff which increases damage taken by 25%. For this reason, players should stay spread out. It is critical that the Crystal Shards are destroyed as soon as possible. At least one ranged DPS with good AOE should be prepared to focus all attention on the adds.

Phase 2 stays the same for tactics, add damage is increased but if hit by the emerge from Corborus you will be killed instantly. Everyone needs to be very aware of the dust cloud's position, while also being sure to keep the adds off the healer and hopefully destroy them before Corborus re-emerges.