Serpentshrine Cavern Guide - Hydross

by Byron Mudry on Oct 16, 2007

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Serpentshrine Cavern Guide Sections

Hydross the Unstable

The first boss that you reach in Serpentshrine Cavern is Hydross the Unstable. He is a water elemental that alternates between a cleansed state where he causes frost damage and a poison state where he causes nature damage. The fight is a constant movement and passing aggro fight.

While he is the first you reach many guilds leave him for a later kill due to his difficulty. He is much harder than Gruul and probably the third most difficult boss in Serpentshrine Cavern.

If you take the time to gear up for the fight though, and then learn the fight through many attempts, you should be able to clear all of Serpentshrine Cavern.

Abilities

Hydross has many abilities that need to be watched for and dealt with. They include:

Phase Shift - Hydross can switch between a pure water form and a poison form. In fact he must be changed between the two forms or you will not be able to deal with him. When dragged out of the area marked by the beams in his room bhe becomes poisoned, when moved back between them he is cleansed again.

Mark of Hydross / Mark of Corruption - This ability is a debuff to everyone in the raid regardless of distance or line of sight. The debuff stacks up to 5 times in one of two ways. It can stack a nature of frost vulnerability debuff, with values of 10%, 25%, 50%, 100% and 250% extra damage from attacks. The debuff is applied every 15 seconds and lasts for 30 seconds. It is not dispellable, but only applies to damage of the type being caused when the debuff was applied. Mark of Hydross applies to frost damage and Mark of Corruption applies to nature damage.

Watery Tomb - Hydross uses this attack while in his water phase only. He attacks with this ability roughly every 8 seconds, and it hits a random non-MT target. Once hit it will stun you for 4 seconds and causes roughly 1000 damage per second. In addition, it will chain to anyone within 8 yards of the target, and then continue chaining as long as someone is within 8 yards of them and so on. Spacing is obviously critical in dealing with this ability.

Vile Sludge - Hydross attacks with this ability roughly every 15 seconds while in his poison phase. It is a debuff that lowers the damage you deal and the ammount you are healed by 50%. In addition is does rougly 500 damage per tick (every 3 seconds) for 15 seconds.

Summon Water Elementals - Hydross will summon water elementals throughout the fight whenever he is cleansed or poisoned. Each time he will summon 4 elementals around him that need to be dealt with. Either 4 Pure Spawns of Hydross which are water based or 4 Tainted Spawns of Hydross which are poison based. They each have roughly 60,000 health and need to be downed quickly.

Enrage - Once 10 minutes has past in the fight, Hydross will become enraged. At this poing his damage goes up significantly and he is capable of one shotting alost anyone in the raid. If he is not within a percent or two of death, enrage means a wipe.

Preparation and Basics

The fight with Hydross is very resistance gear intensive on the tanks. All the tanks must have a set of resistance gear that is maxed for level 70. Two of them need to be maxed frost resistance and two maxed nature resistance. In addition they will need to have high health pools as once debuffed with Hydross's Mark you will be taking hits of up to 11,000 health. All the damage incoming is going to be either nature or frost, so armor values do not play as huge a roll. The resistance gear really needs to be farmed for by the whole guild as it will cost upwards of 4,000 gold per tank to acquire the gear.

GEAR! Gear is critical for this fight. Hydross is a gear check fight for the whole Serpentshrine Cavern raid. Everyone in attendance must have Karazhan quality gear or higher. Players in greens need not apply. Players with more than a few (2-4) blues should consider their attendance as well. In addition, every slot needs to have the best possible gem and enchant placed on it.

Patience, grasshopper (I always wanted to use that line). Even if you have the best gear possible and your tanks have the required resistance gear, the fight is hard. Be prepared for many attempts and deaths.

Tactics

The fight starts by charging Hydross while in his purified stage and fighting him on the platform. You will fight him there for roughly the first minute, all of which will be without adds, until you reach 4 Mark of Hydross debuff's (100% bonus damage). At this time you need to move Hydross out of the two beams.

When he exits the area between the two beams, a few things happen. First he drops his aggro table, secondly he summons 4 tainted elementals (poison in this case) and lastly he changes to his poison phase. In this stage he will be casting vile sludge on a target. Have a healer assigned to watch for the person affected and keep them alive.

You need to have everyone be extremely careful at this stage, as the nature resist tank needs to pick him up from zero threat. If he is pulled back by someone into the beam area he will change back to his purified form and summon an additional 4 adds, which is not something that many groups can handle, at least while learning the encounter. Warlocks and shadow priests need to stop DOTs on him a few seconds before the transition so that they do not pull aggro.

The adds need to be crowd controlled while the tank is acquiring Hydross, and then killed. Once the adds are dead you need to get all DPS back on Hydross. You have about 1 minute to get the adds down and do as much damage to Hydross as possible before you have to reverse the process and drag him back into the area between the beams.

This time he will summon 4 pure elementals, clear aggro and change to his cleansed form. Repeat the process above to kill the adds and get back onto Hydross. In this stage Hydross will be casting water tomb every 7 seconds. As with the poison stage, you need to have a healer assigned to heal this as soon as it starts. When you are nearing the 1 minute part of the fight with the 100% damage debuff on it will be hitting for 9000 damage in 5 seconds, to many players this could mean death unless they get a heal before it completes.

The sequence is then repeated until you kill Hydross, he kills you, or 10 minutes elapse at which point he enrages and kills everyone with 1 hit a piece.

At each change of phase it is critical that the new tank is ready and stacks aggro as fast as possible. It is equally important that everyone switch to the new side of the beams to ensure that if they do pull aggro that they do not trigger more adds to spawn. DPS really needs to be extremely careful and not touch Hydross for about 4-6 seconds after a transition at all, and if anyone does start dpsing him, to be careful of threat for about the first 15 seconds (when first debuff is applied). It will take about 30 seconds to down the adds anyway.

Since the fight has a 10 minute time limit you can easily see if you are doing enough DPS at any stage. Your goals are to have hydross down to 80% before the first transition (since you will have no adds to deal with), and then 10% per transition after that. This gives you 1 spare transition at the end to catchup any DPS that you are behind. If you are significantly behind those marks while learning the fight, you likely need to continue to farm Karazhan and Gruul for better gear.

The fight is a very test of coordination and teamwork. It is also a good learning fight, if you can down Hydross, you are ready for anything in Serpentshrine Cavern. You may need some gear upgrades for later bosses, but you will have learned to work together well enough to defeat them once you have the required gear.

Serpentshrine Cavern Guide Sections

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Last Updated: Aug 03, 2021