The expansion is so close I can taste it. Once everyone gets themselves to 80, Naxxramas is going to be on the menu so I think it is worthwhile to talk about some of the encounters so people will know what to expect before they get there. There have certainly been some tweaks to the encounters to balance them for 10/25 people, but the broad strokes and major mechanics are the same as they were in the 40 man version. I haven’t played in the beta and I haven’t read anything about how encounters have been altered so don’t rely on this as gospel.
The first boss in the spider wing is Anub’rekhan and it is a pretty simple fight once you get the movement right. The room is a big circle with the boss at 12 o’clock and he is flanked by two crypt fiends. On the pull the MT runs straight through the boss and pull him back towards the alcove at 12 o’clock. The other tank/tanks need to bring the crypt fiends to 9 o’clock. The crypt fiends have a stacking buff that increases their damage and attack speed so if they are left alive for too long, they will kill the tanks. So the dps needs to kill the crypt fiends before they start working on the boss. But the crypt fiends can cast an immobilizing web wrap on the tank. A pally tank should be able to BoF out of the web wrap, druids should be able to shift out and a warrior with warbringer should be able to intervene to someone to break the snare so it shouldn’t be a big problem, but the dps needs to be aware of it because killing the crypt fiends before they get to the 9 o’clock position can cause big problems.
Once the crypt fiends are dealt with, dps can switch to the boss. Most ranged dps and healers should be standing in the middle of the room on the big green circle. But you want to have a mage or two standing at 9 o’clock where the crypt fiends were killed. The boss has an ability called Corpse Explosion that he can cast on any corpse in the room – players and NPCs. When the boss explodes a corpse, a bunch of scarabs spawn and they don’t have a lot of HP and they don’t do much damage, but if any of them aggro the MT, you are in serious trouble. So you have your mages on top of the crypt fiend corpses so that when the scarabs spawn, the mages can frost nova them and AoE them down.
The boss also has an ability called Impale that targets random people in the raid. That person, and anyone near them get launched up in the air. The impale does some initial damage and then the people take fall damage as well. Between the initial hit and the fall damage, Impale will take roughly 50% of your HP. There isn’t any raid damage other than Impale so it should be easy to keep everyone topped off and then Impale won’t kill anyone. It important that no one gets killed by impale because it would mean a corpse in the raid and therefore scarabs spawning out of position so they don’t get taken out by the mages.
Now for the fun part. Roughly every 100 seconds the boss uses an ability called Locust Swarm. Locust Swarm hits everyone within a 30 yard radius of the boss and afflicts them with a stacking dot that does a whole bunch of damage and it applies a total silence/pacify effect – you can move around but you can’t do anything else, not even auto attack. The dot does enough damage that it will pretty easily kill the tank if he gets more than a few stacks. But Locust Swarm also reduces Anub’rekhan’s movement speed by 40%.
Around the outside edge of the room there is a mote of green slime that doesn’t go quite all the way to the wall. The MT is going to position himself so that the small ledge on the outside of the slime is directly behind him so that when the boss starts the 2 second Locust Swarm cast, the tank can immediately turn around and start kiting the boss. The tank has to take extreme care not to touch the green slime because it reduces your stats by 50% for a few seconds. The tank also has to take extreme care not to run into the wall and get caught up for a second because if the boss catches the tank, the tank is probably going to die. You are going to have a hunter in the tanks group who is also on that ledge and when the boss starts the locust swarm cast, the hunter will turn on aspect of the pack. The run speed increase from AotP is enough so that the tank can safely out-range the boss while Locust Swarm is active.
If the scarabs that spawn from corpse explosions aren’t managed properly and one of the aggros the tank, then the tank will get dazed while AotP is up and he will take too many stacks of the dot and he will die. If the tank clips against the wall and gets meleed by the boss, he will get dazed and take too many stacks of the dot and he will die. If the hunter is slow turning on AotP then the tank won’t be able to get away from the boss and he will take too many stacks of the dot and he will die. It is important for the healers to put HoTs on the tank before he starts the kite because even if everything goes well, its still possible for the tank to get 1-2 stacks of the dot so having HoTs on the tank is important.
The tank will kite the boss from 12 o’clock, around the outer edge of the room, through 3 o’clock and down to 6 o’clock – where you entered the room. In the time it takes for the tank to do the kite, Locust Swarm will have run its duration. The tank will resume tanking the boss and will get him positioned so that he can kite back up to 12 o’clock along the same side of the room when the boss casts Locust Swarm again. Also, when the boss casts Locust Swarm, a new crypt fiend spawns at 12 o’clock and the OT will have to pick it up and drag it over to 9 o’clock. If the OT tries to run over to the new crypt fiend it is likely that he will get hit by Locust Swarm so the tank ought to wait in the raid for the crypt fiend to come to him or have a hunter MD it to him. During the kite phase, there is no reason for anyone to be DPSing the boss, doing so only puts them in a position where they are likely to be hit by Locust Swarm. Instead, all the DPS should be waiting for the crypt fiend to get into position and then burning it down.
The fight really comes down to how well the tank can do the kite. It may take a few pulls for the ranged/healers to figure out that taking risks in the fight is a bad idea and that they just needs to GTFO when Locust Swarm is coming and it may take a few pulls for the tank/hunter kiting team to figure out how to run the narrow path between the slime and the wall, but once you get that squared away, its just rinse and repeat.