Pull him forward to the narrowest part of the hallway behind him, tank him backed against one of the walls. When he does the knockback ability, the tank won't be thrown away. When he is charging Ground Slam, move directly through him to the other side, backed against the other wall.

Tank
Indeed, this *is* a tank fight; however, it's important to know how the abilities *actually* function. The boss does a trio of abilities that require a quick adjustment by the tank; otherwise, an incredible amount of damage is taken from one of two heavy-hitting abilities. Contrary to earlier posts, the sequence of events is actually PARALYZE - SHATTER - GROUND SLAM. It just so happens that the fight begins with an isolated GROUND SLAM; consider this your warning wake-up-all to start paying attention. After that point, you'll continue to do normal tanking things, but your absolute priority is to avoid taking damage from that trio of abilities.
When you see PARALYZE being cast, you know that you're about to be stunned in place. This is very bad, since SHATTER and GROUND SLAM will do incredible amounts of damage (upwards of 100,000). The way to avoid this damage is to inflict the boss with a DoT. Right before PARALYZE, the boss will enter a spell-reflect phase. At this point, if you put some type of DoT on the boss, it will reflect back to you, and will wake you from PARALYZE. This is vital. If you do not have a DoT, you must be dispelled, so you're able to do the SHATTER/GS dance.

Okay...Once you're free from PARALYZE, you will wait for SHATTER to begin casting. Once you see it (if you time it well, you can move before you even see the castbar) you must immediately move 25 yards away from the boss (who is, at this point, stationary). The easiest thing to do is to strafe to a position where rDPS can still hit the boss (and where your healer can still heal you). While you are moving, the boss will finish casting SHATTER. As soon as SHATTER is done being cast, you must move 8 yards away from the position where you were when the boss finished casting SHATTER (this was ambiguous in earlier postings). The best thing to do here is to move directly back at the boss (which is easy if you're feral or a warrior, since you can just charge back in). As a Prot Pally with PoJ, you'll be just fine. DKs may want to use UHP if it's easy to reach; otherwise, just react quickly. At this point, the boss will have finished casting SHATTER, and you'll avoid the damage spike (literally) by running back at him.

In the next instant, the boss will begin to cast GROUND SLAM. This is the second very heavy-hitting ability. You must escape this, and if you're running at him (as above), continue to run through his body until you're behind him (and past by 8 yards). That's it; that's all 3 abilities avoided. Then, simply begin your tank-and-spank rotation until the next PARALYZE happens (which you'll pick up from some audible clue, which is the boss shouting something about "breaking yourself on his body". Rinse, repeat, profit.

Tank
This is a tank fight. If the tank fails, your group will wipe.
Clear the mobs outside the tunnel. Position your group as a triangle. The top of the triangle being the boss inside the tunnel. The tank outside to the left of the tunnel. The rest of the group outside to the right of the tunnel.

The tank will feral charge, charge, or run into the boss. Tank Boss inside the tunnel.

There are two two skills to watch out for. GROUND SLAM and SHATTER. If you get hit by any of these 2 skills, you will DIE!

At the start of the encounter, the boss will always ground slam first. This can be avoided by strafing to the left or right. DO NOT run through him to try and avoid it. When you do this, you are not attacking. You will screw yourself over if he casts paralyze right after and you do not have the bleed debuff on you!

He will always cast shatter sometime after a ground slam. The tank must IMMEDIATELY run 25 yards away from the boss (where the tank first stood in the triangle - basically run through him). When shatter finishes casting, you can feral charge, charge, or run back to him in the tunnel. Tank him in the tunnel.

With the triangle strategy, the healers/range will never get hit by a ground slam or shatter.

Also make sure in your camera settings, make sure the tank has "Only Horizontal when moving" selected. It will make things easier after feral charging/charging and when turning/strafing/moving back and forth etc.


Tips
When the boss starts casting paralyze (which has a .5-1 second cast time), you can already start moving to run. He will always shatter after paralyze.
If you think you are going to die to a shatter, you can pop all tanking cooldowns. This may or may not save you from the shatter.
If you think you don't have enough time to run out of a shatter, druids can stampeding roar in bear from. If you are a worgen, you can use darkflight. Priests can also Grip you out of a shatter.
You can also abuse LoS to avoid shatter, but with the triangle formation, you should never have to.

Melee DPS
Melee DPS must always run when boss casts shatter.
Sometimes the might screw up (don't blame the tank! it's a really hard fight!), and the boss might face other melee DPS when he casts Ground Slam. The melee DPS need to strafe to avoid it.


Healers/Ranged DPS
You must always have a DoT on him or else you cannot break out of paralyze (8 second stun). Healers can also cleanse paralyze on range DPS that cannot DoT or forgot to put a DoT up.
Paladin healers are the only healers without a DoT. You can either Trinket/Bubble/etc to remove paralyze or get somebody else who can can remove magic remove it off you.

If worse comes to worse, buy some Sulfuron Slammer from the bartender in BRD. This item leaves a damaging DoT on yourself for six seconds. Make sure your finger is always on the button to use this item cause Paralyze has a short cast time (or you can predict when he's going to paralyze and use it before)

Hunters will have to use Sulfurion Slammer or getting someone to clense them since the boss doesn't reflect any of the hunter's DoTs back at him. The other option is for the hunter to run up and melee the boss after he casts Elementium Bulwark to gain the bleed effect. The bleed will break the hunter out of paralyze. The hunter must immediately get out of range of the shatter, preferably with Disengage.