The Underbog is the second instances in Coilfang Reservoir. It has four bosses, total. Here is the strategy to beat the first and second boss.
Hungarfen
The first boss is Hungarfen. He has two abilities, and they involve bog mushrooms. One spawns a mushroom that does 360 damage every two seconds and can stack up to five times. You must move out of this when it spawns. The second one is Foul Spores, which is an AOE poison cloud that does 400-600 poison damage every second. It also heals Hungarfen for four times that amount.
The trick to this fight is to have the tank move him out of the mushrooms until 20%, then move away during Foul Spores. Hungerfen will not move so he will not be able to heal himself. If you stay in the spore cloud he will heal himself and make it very hard to kill him.
Then, the tank can agro him when the spell is over.
Ghaz’an
The second boss in slave pens is Ghaz’an. This fight is simple if done right. He has three abilities to watch out for. His Acid Spit does 2000 nature damage to those in front of him. His Acid Breath stacks up to five times and does 2000 nature damage and 155 additional damage over five seconds. His Tail Swipe does a knock back and inflicts damage.
Have the tank aggro the hydra and drag him down the ramp. The tank should hold him against the wall because Ghaz’an’s knockback can throw the tank off the platform and into the water below. This will result in a raid wipe. The raid’s DPS should either stand back down the hall, out of melee range, or do melee while standing at his belly to avoid the tail swipe. To learn more about World of Warcraft try reading the Team Idemise Guide.