The Northrend Beasts is a three phase boss fight. You first fight Gormok the Impaler, then Acidmaw and Dreadscale at the same time, and finally, Icehowl.
Phase 1: Gormok
Phase 1 has four simple objectives:
* two tanks taunt off each other to keep the damage-over-time Impale from stacking too high (more than 3 debuffs)
* raid DPS kill Snobold adds that attach themselves to random players
* ranged and healers spread out to stay out of fire patches and outrange the 15-yard staggering stomp interrupt
For the two tanks, taunting as the Impale debuff is about to wear off can keep the debuff at 2 or less for most of the encounter, with little risk of it restacking on the same tank. After the first taunt, the tank should let his stack fall off and taunt again.
The ranged DPS and healers must avoid fire patches that Gormok puts down. These patches deal fire damage every second in a small radius, and Gormok can put down several in rapid succession--moving from one patch to another that spawns can occur, and for this reason, the ranged and healers should spread out at least enough to avoid chaining these patches (similar to Napalm on Mimiron).
Lastly, Gormok will throw Snobolds on random players (anyone is a valid target, even a tank). These Snobolds regularly stun and kick their targets, making them a big impediment to the raid if they land on a healer. If this happens, at least the ranged (if not all DPS) should kill the Snobold, as several Snobolds on healers can easily incapacitate them and cause problems for the tanks.
Phase 2: Acidmaw and Dreadscale
The key mechanics to understand about this phase are the interactions between Burning Bile and Paralytic Toxin.
* Acidmaw applies Paralytic Toxin; Dreadscale applies Burning Bile.
* Players with Paralytic Toxin can get it removed by running to players with Burning Bile and taking a tick of fire damage.
* Burning Bile falls of naturally and cannot be removed.
One tank takes Dreadscale, the other Acidmaw. Dreadscale enters on the right facing the outside door and is mobile; Acidmaw emerges from the ground on the left and is stationary. The two worms burrow periodically, switching which one is mobile and which is stationary. The mobile worm puts down poison clouds at regular intervals, like Grobbulus, and thus must be moved out to keep it safe for melee and for the tank.
Until the first burrow, the Dreadscale tank will always have Burning Bile, and Acidmaw may attack any cluster of players, giving them Paralytic Toxin. These players need to move to the Dreadscale tank, take a tick of AoE fire damage, and thus clear their debuff, lest they become paralyzed and stunned. This applies to the Acidmaw tank as well, who can run from Acidmaw without fear of losing aggro, even though it is stationary.
After the first burrow, Acidmaw is mobile, and Dreadscale stationary. Dreadscale will now apply Burning Bile not just to his tank but to a random raid member and anyone around him. This creates an AoE damage hazard, as all these players must spread from each other and from other raid members--they will deal AoE damage to anyone around them an themselves.
A simple strategy is to burn down Acidmaw, as then no one will need to clear the Paralytic Toxin debuff, and Burning Bile by itself is not much of a threat. The Acidmaw tank need only make sure he gets his Paralytic Toxin debuff cleared, either by running to the Dreadscale tank or vice versa, if Dreadscale is the stationary worm at the time.
Note that when one Jormunjar dies, the other enrages, for at least 50% extra damage (10 and 25 player normal).
Phase 3: Icehowl
Aside from Icehowl's melee range knockback and periodic tank stun, the main mechanic of this phase is the Massive Crash and charge mechanic.
* Icehowl knocks the entire raid back to the walls, stunning them
* Icehowl picks a random target to charge and runs to the opposite side of the room
* All raid members gain a speed buff to run away from the target area
If improperly executed, one or more players will be hit by Icehowl, will take upwards of 60,000 damage, and die. Icehowl will then enrage, which, in a pinch, can be dispelled by Tranquilizing Shot or Anesthetic Poison.
If done right, however, Icehowl will hit the far wall and stun himself, increasing damage taken for a short period. This is the ideal time to reconvene and pop short cooldowns. Avoiding the charge is critical to minimizing overall damage to the tanks and maintaining control over the phase. Other than that, healers need only watch out for the freezing cone attack, which can be broken altogether if the main target breaks the stun (Blink, or usual immunities like Divine Shield).