Hydross the Unstable Strategy Guide (SSC)

tbc classic hydross the unstable strategy guide (ssc)

Traditionally, Hydross the Unstable will be many groups’ first boss encounter after entering Serpentshrine Cavern. On this page we will go about breaking down his abilities, strategies, gearing, and positioning to offer you the highest chance of success.

Abilities/Key Notes

  • Whenever Hydross switches form, he will summon four Elementals matching his new form
  • Like many other bosses, Hydross is immune to taunting effects
  • He has an Enrage timer of 10 minutes
  • His Elemental adds deal roughly 6,000 Frost/Nature damage, have roughly 50,000 health and are immune to their respective elemental (Frost adds are immune to Frost damage, for example)

Different Forms

Water Form

  • Melee: 5-6,000 frost damage
  • He is immune to Frost damage in this form
  • Mark of Hydross: Raid-wide debuff that will increase Frost damage taken by 10-500% (10, 25, 50, 100, 250, 500)
  • Water Tomb: Small radius AoE ability that stuns all affected players for 4 seconds and deals 4,500 Frost damage over 5 seconds

Note: It may be beneficial for your raid members to stay slightly spread out from each other to avoid being damaged and stunned by other random players targeted with Water Tomb

Poison Form

  • Melee: 5,000 Nature damage
  • He is immune to Nature damage in this form
  • Mark of Corruption: Raid-wide debuff that will increase Nature damage taken by 10-500% (10, 25, 50, 100, 250, 500)
  • Vile Sludge: Debuff that causes 4,000 Nature damage over 24 seconds, reducing damage and healing by 50%

Raid Preparation

Raid Composition

  • Ideally, each raid should have one tank with maxed out Frost Resistance (The “cap” for elemental resistances is 365)
  • Each raid group should also have one tank with maxed out Nature Resistance
  • 2-4 tanks with an assortment of both Nature and Frost Resistance gear (Two would be the minimum)


tbc pve ssc hydross the unstable positioning 2

For melee DPS, you will be moving with Hydross, so on each phase, it’s best practice to change a few yards forward and backward. As another best practice, all other raid members should set up spread out, as a means to reduce the effect of Water Tomb. The red line drawn above represents the line that Hydross must pass in order to switch between his forms.

The Fight

It should be noted that the Tainted Water Elementals nearby will continue to spawn until the boss encounter is started. So, it is ideal to have a tank, healer and some DPS kill those so that they will not participate in the boss fight as adds.

While Hydross begins the encounter in his Water Form, it should be noted that it is VERY easy to immediately have him switch forms, effectively summoning four adds immediately. This is done if he is pulled normally (Pulled from afar, body-pulled, etc.) To combat this, a Druid can use Feral Charge to close the gap immediately, or your plate-wearing tanks can use either Lesser Invisibility Potion or Invisibility Potion and then begin the fight next to Hydross. The challenge is to reach him before he crosses the magical “boundary” that is located approximately between the two small flags in front of him.

The main concern for the tanks during this encounter is the stacking debuff, Mark of Corruption and Mark of Hydross. Before you reach even 5 stacks, it is possible to be one-shotted. To combat this, it’s best to let 4 stacks be applied, and then move Hydross over the boundary.

Once Hydross is moved across the boundary and switches forms, it’s crucial that all DPS stop attacking (this includes DoTs, too!) since, like Attumen the Huntsmen in Karazhan, the threat table is reset. The concern here is that it is very easy for a DPS to pull aggro and move Hydross back over the boundary, potentially causing a wipe.


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2 years ago

Unsure if you’ve been monitoring what is happening on the PTR, but warriors/druids/paladins are main tanking Hydross with under 300 nature/frost resistance total with buffs (and downing the boss quite easily). You also only need 1 paladin tank with an assortment of both nature/frost resistance to tank the adds.

2 years ago

I am curious about the MOTW and FR Aura. They arent stackable are they?

Reply to  Kurathis
2 years ago

Also, tanks can put another DPS piece on for threat set, can’t they? As Hydross does not crush/crit or you do not need anywhere near def cap, yes?

The Weg
The Weg(@the-weg)
Reply to  Udderheals
2 years ago

Hydross can’t crush but he and his adds can crit.
It’s doable without being crit immune but it’s quite risky and I would not recommend that.

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