Hydross the Unstable (Flex Heroic)

## Overview

Hydross the Unstable is the first boss of Serpentshrine Cavern, and comes in two forms, **Purified Water (Frost)** and **Corrupted Poison (Nature)**.

It has 7,9M at a raid size of 10, which is the minimum health scaling, increasing with 10% per player above 10 up to 25 players.

This boss has a 10 minute enrage timer.

## Overall Abilities

#### Fierce Blow

This is a special melee ability that has a chance to trigger every 3 seconds.

#### Tidal Wave

This is a special ability similar to a Geysir, having a ground visual indicator. Anyone not standing in the ground effect will take between 8000 - 10000 damage. Tidal Wave will first happen after 30 seconds and then every 45 seconds, delayed 2 seconds every **phase change**.

#### Phase Change

Hydross the Unstable exists in two forms, and you can transition him at will by moving him over a line. The line is vaguely marked by two banners on each side of Hydross. Every time you transition him you will have a 2 second grace period, which will postpone all abilities by 2 seconds, **and reset all threat.**

#### Expunge (Purification / Corruption)

Phasing will also trigger the Expunge: (Purification or Corruption) ability, granting you a debuff making you take 50% increased damage from the School of magic you transitioned from, for 30 seconds.

#### Summon Water Elemental (Frost / Nature)

Transitioning Hydross to a new phase will spawn 4 Water Elementals of the same school as Hydross, either Pure Spawn of Hydross (Frost) or Corrupted Spawn of Hydross (Nature). Transitioning again or killing these Water Elementals will create puddles that will damage players and heal Hydross. On Flex Heroic difficulty, these puddles will dissipate after a while.

## Purified Water (Frost) Abilities

#### Mark of Hydross

Mark of Hydross is a debuff ability that applies to all players every 3 seconds, doing 1125 - 1500 Frost damage and increasing Frost damage taken by 10%, stacking up 100 times, lasting 30 seconds.

#### Water Tomb

Water Tomb is a special ability that captures a player and everyone within an 8 yard radius within a frozen tomb, disabling them and inflicting 1000 Frost damage every second, lasting 4 seconds. It will happen initially after 10 seconds, and then every 45 seconds. It will however be pushed by phase transitioning and coinciding with Tidal Wave. This ability shares a cooldown with Vile Sludge.

## Corrupted Poison (Nature) Abilities

#### Mark of Corruption

Mark of Corruption is a debuff ability that applies to all players every 3 seconds, doing 1125 - 1500 Frost damage and increasing Nature damage taken by 10%, stacking up 100 times, lasting 30 seconds.

#### Vile Sludge

Vile Sludge is a special ability that coats a player and everyone within an 8 yard radius in Sludge, reducing their damage and healing done by 50% and inflicting 1000 damage every second, lasting 12 seconds. This ability shares a cooldown with Water Tomb.

## Tactics

#### Line up

Hydross is very flexible when it comes to line up. It can be 1 tanked, but 2 tanks are suggested for handling adds and positioning them a place where puddles aren't in the way. You can also have a full melee composition, as long as you spread during the Frost Tomb and Vile Sludge mechanics.

For efficient raid movement it is advised to tank him close to the transition line, and let healers be close to the lines. The damage dealers that are the least affected by movement should be positioned on the far side. The secondary tank would be in charge of tanking the Water Elementals to a remote location, but not too far as he would need to move back for Tidal Wave.

Hydross 2 tankingHydross solo tanking

#### Purified Water (Frost)

On pull, Hydross the Unstable will be positioned within the Purified Water area, dealing Frost damage. That means the initial ability he will cast is **Frost Tomb**. Ensure that all players are inside the Purified Water area and spread with 8 yards inbetween them. After Frost Tomb happens, everyone can group up in melee range, while watching threat. This is because **Tidal Wave** will always be within walking distance of the boss. After Tidal Wave your raid spreads out again until transitioning or next Frost Tomb.

Mark of Hydross will continue to stack while being in Purified Water phase, every 3 seconds, which lasts for 30 seconds. This means every phase after the first transition has to last atleast 30 seconds for the opposite stacks to drop. The amount of stacks you'll push every phase depends on your healers, with a natural limit around 21 stacks (1 minute) where every tick of Mark of Hydross can be fatal.

#### Corrupted Poison (Nature)

When transitioning Hydross, it's important to cancel attacks to let the tank establish threat while also relocating to the Corrupted Poison area. If you don't relocate and continue to damage, you might pull threat and instantly transition Hydross back, killing the Water Elementals and spawning puddles in very bad positions. In this phase he will deal Nature damage, and it's important to note that Tidal Wave is on a set timer, and can happen in both phases.

Same tactic apply, spread until Vile Sludge happens and then continue to stack for Tidal Wave, or directly stack for Tidal Wave if it is imminent, as it will push the timer on Vile Sludge / Water Tomb.

#### Tips & Tricks

Aspect of the Wild (or Nature Resistance Totem) will give you an initial 70 Nature Resistance, granting a 16,6% reduced Nature damage taken if you previously had 0. (40 yards) (For more information, click here)

Frost Resistance Aura (or Frost Resistance Totem) will give you an initial 70 Frost Resistance, granting a 16,6% reduced Frost damage taken if you previously had 0. (40 yards)

If you would like to extend any of the phases, then it's highly suggested to use damage reducing abilities such as Barkskin, Divine Sacrifice (If invested into 2/2 Divine Guardian, which can be coupled with a /cancelaura macro) and even Aura Mastery (Frost Resistance Aura).

```
#showtooltip
/cast Divine Sacrifice
/cancelaura Divine Sacrifice

```

*Written by Barsk*