Cleaves and Tail Smash

As a typical dragon, Sindragosa likes to cleave and Tail Smash.   So if you're in front of her, she can cleave up to 10 people.   If you're behind her, she'll smack you, knocking you 40 yards away or so.

The raid, well, has to run in avoiding that.  Everyone just stay away, pick a side to all group up.    The tail smash in particular is an aoe from the point of impact, so you want to be a little more towards the front than the usual hind legs area.

We decided to position her facing 90 degrees from where you enter. Always facing the south (I think, left side when facing in). It's probably not a huge deal and can face any direction as long as the raid is adjusted for it.

Frost Aura

Next thing of note is that she has an aura that hurts the raid throughout the fight.   Doing 4500 Frost Damage every 3 seconds, 3000 damage in 10 mans.

So like Sapphiron, Festergut, Blood Queen, and many others, something for the healers to keep busy with. 

There isn't any aoe to note of on this phase.  So the raid can group up to one side of her to maximize chain heals and other assorted aoe healing.

Frost Breath

Sindragosa also deep breaths, I mean Frost Breaths.   It's a 37,000-43,000 frost damage frontal cone attack, which also decreases movement speed by 15%, and attack speeds by 50%.

So, the raid should never be in front of Sindragosa.   Except the tank.   Even then, healers gotta be prepped for this spike damage.   It's a 1.5 second cast, so if you can time CDs to pop with it, go for it. Frost Resist gear will mitigate this significantly.

This is also involved in the Shadowmourne questline.  Get hit by this 3 times without dying, and killing Sindragosa.  So, if you're not the MT for this fight, you're gonna have to pretty much bribe your healers to save your ass for this.   Thrice.

Unchained Magic and Instability

On some timer and going out to several casters in the raid...   Unchained Magic is a 30 second debuff that makes each of your spell casts put another debuff on you, Instabiliy.

What Instability does is 8 seconds after your spell cast, it'll do 2000 arcane damage to you.  Each additional spell cast you do within that 8 seconds, stacks it.    So, 4000, 6000, 8000, etc.

This means, casters, dps, healers alike, can't be just chain casting spells.   Stop/slow down dps/healing, or you could wind up killing yourself quite quickly.

Healers likely will have to call out and tag someone else into do their healing spam for them while they slow/stop theirs to wait it out.    Either way, likely key to this is to communicate.

On 10 man, it just seems to almost always target 1 healer, and 1 dps. And maybe, the 1 that's doing highest dps/hps in between the debuff periods. This is speculative and seemed to be that way every pull on our kill.

Shadow Priests and Mages can almost ignore this mechanic, but still pay attention to it. Can stack it as high as you want, then use Ice Block / Dispersion to take the backlash damage. So this likely occurs during Air Phases, but still keep an eye on the stacks and your CDs to get through it.

Permeating Chill and Chilled to the Bone

Not to leave the melee and hunters out, they get their own kill themselves mechanic as well.   In their version, each physical attack done on Sindragosa has a 20% chance of applying that Chilled to the Bone debuff.

That would be a 1000 Frost Damage per 2 sec DoT, and of course, it stacks.

So, fast attacking melee...   Good luck!  Watch your debuffs, stop attacking if the DoT gets too high for your healers.  Frost Resist does help your survivability, at the cost of dps itself of course.

Tanks, even you might need to stop attacking to let the stacks fall off.  So might want to call that off so DPS can "chill" while you're not doing threat.    Or maybe they'd be doing that anyways with their own debuffs to worry about.

Icy Grip and Blistering Cold

On some timer, she'll cast Icy Grip, which pulls everyone into melee range.    Think a bit like Azuergos, or Cyndragosa.

After accomplishing that, she'll start a 5 second cast for Blistering Cold, 35,000 Frost Damage to anyone within 25 yards.

So raid, run!   Run little girls run!   

Maybe the tank can stay in, maybe.  Might need a CD and fast heals.   Otherwise, run out, charge back in.

Warning: You can apparently resist the Icy Grip. One part good that you're not closer to Sindragosa when she starts the cast. One part bad in that you many not notice she started the cast. So pay attention!

Frost Beacon

The raid should group up, except those that are marked with those beacons.   Sindragosa will mark 5 of them in the 25 man, 2 of them in the 10 man. 

We use a "Wall Strat", in which first the entire raid groups up on the stairs. Then, the 5 beacons are to run to the bottom of the stairs and spread out along it. So you'd have 1 in the middle, 1 on either end, and 1 in between each of those. We used the Boss Mod's order of calling out people to position everyone. Example, first one called goes to far left, etc, last one called goes to far right. That pattern.

Icy Tomb and Asphyxiation

Encases each of the Frost Beacon targets in an Ice Block.   The Icy Tombs can be attacked, and should be to free them.   They have about 786K hp in the 25 man. 

These do about 10K damage on impact and chains the Ice Tombs, a bit similar to Hydross bubbles. So they should be spread out, and the raid should get to them after they're formed.

Asphyxiation will start after some time in the blocks, it damages them for 8% of their maximum hp per second, so top them off before it hits and free them before they die.

Frost Bombs

She will be launching 4 of them at us, one at a time.   The ground will be glowing and have a small blue-white targeting reticule where the bomb will be hitting.   It does 23-27K Frost Damage to everyone within Line of Sight of the point of impact.   Well, those Icy Tombs can be used to LoS it.   

So as the Frost Bombs comes down, the raid is to shift around the Icy Tombs to always be on the opposite side.  While dps'ing them down to free your raid members.   But not dps'ing too fast to release all the tombs before the 4th Frost Bomb.   Pace yourselves, like only kill half the tombs after a 2nd Frost Bomb is done, then save the last one til the last one is done.

She will land back on the ground after the 4th Frost Bomb hits. Ground Phase begins again for another 1:50.

Frost Beacon and Icy Tomb

Just like the Air Phase, she'll probably do this on some timer.    The marked raid member should run out of the raid to not chain the Icy Tomb to everyone else.

Set your raid up into 2 ranged camps, both a bit away from Sindragosa. One will be around her midsection, the other will be around her head. Keep the middle/melee area clear. The Ice Tombs are to run into the middle and drop it in front of one of the camps without chaining it. This allows them to use it as a LoS. The ranged/healers are to make sure they stay back to not chain Ice Tombs.

In the meantime, the melee are to DPS the Ice Tombs down. They would be running Tomb to Tomb, and maybe Sindragosa if there's time. But always keep away from where the next Tomb is going to be until it is formed. Do not chain it.

Mystic Buffet

This is a debuff that increases magic damage taken by 15%, per stack, can be LoS'd.   So this is why you want to leave an Icy Tomb up.    Use it to drop off your stacks when they get high. 

You will need your 2nd tank in this phase only.   Kinda like how Putricide throws an extra tank in the last phase.   This would allow your main tank to go get LoS himself to drop off his stacks.

Anyways, that's all to the fight I believe.  Good luck!