This instance is in the Barrens, south west of the Crossroads, just north of an oasis. The entrance looks vaguely like a skull; in the top left eye as you face it are some of the quest givers. You can only reach them by climbing up the hill above the skull, and jumping down carefully.
Mobs are 15-21. There are relatively few linked mobs, although the deviate guardians will call for help, and some of the druids have several (non-elite) helpers – pythons to the west, and little plants to the east. The plants could do some damage if you ignore them.
The east side of the map is extremely convoluted, with several places where jumps can short cut between passages – although you can navigate all the way without ever leaving the ground.
Mebok Mizzyrik, Ratchet – Smart Drinks (Raptor Horns is a prerequisite)
Crane Operator Bigglefuzz – Trouble at the Docks
Apothecary Zamah, Thunder Bluff (Horde) – Serpentbloom
Nara Wildmane, Thunder Bluff (Horde) – Leaders of the Fang
Ebru (above entrance) – Deviate Eradication
Nalpak (above entrance) – Deviate Hides
Glowing Shard (random drop in WC), take to Sputtervalve, leads to:
Falla Sagewind, Barrens – In Nightmares
There is also a quest from the Disciple of Naralex, just inside the entrance to the instance. This triggers when you have killed all the leaders of the fang, and involves fighting a few waves of mobs by Naralex. Each time you talk to the Disciple, he gives you Mark of the Wild.
Mad Magglish is a stealthed goblin in the area outside of the Wailing Caverns. There are two spots that he hangs out in: one is to the left as you enter, in a passage going back with a bedroll on the floor; the other is in a niche on the right, not far from the entrance.
It is just barely possible to gather serpentbloom without having to fight the elites; one should spawn on the left close to the entrance. It will take a long time to gather enough to complete the quest if you try this.
The two deviate quests and the glowing shard quest can be done by Alliance; the final part of the Glowing Shard requires delivery to Thunder Bluff, but Alliance can instead hand in to Darnassus.
For the deviate hides, they both drop and can be skinned. However, they are rare – one person clearing the instance only just gets enough for the quest, with skinning. A group would require multiple runs. As the reward is a leatherworking pattern to use deviate scales, which also aren’t common, plan on spending a lot of time in here if you want to pursue this quest to the fullest.
Boahn – 20 elite, spawns outside the instance and is stealthed; drops Boahn’s Fang, a two handed axe (blue, BoE). Also Brambleweed Leggings (leather).
Kresh – the tortoise; drops Kresh’s Back, a blue BoP shield, relatively rarely.
Lady Anacondra – Belt of the Fang (BoP), Barbed Club of Strength (mace), Serpent’s Shoulders (yellow leather).
Lord Cobrahn – Cobrahn’s Grasp (mail belt), Leggings of the Fang. Both blue and BoP.
Lord Pythas – Stinging Viper (blue, BoP). one handed mace; Armor of the Fang (BoP).
Lord Serpentis – Venomstrike (blue, BoP), bow; Footpads of the Fang (BoP).
Mutanus the Devourer – Deep Fathom Ring, Slime Encrusted Pads (cloth shoulders), Mutant Scale Breastplate (mail). All blue and BoP.
Skum – Glowing Lizardscale Cloak (blue, BoP); Tail Spike (green, BoP), dagger. Big lizard.
Trigore the Lasher – Serpent’s Kiss (blue, BoE), one handed axe; Runescale Girdle (green BoE, mail waist). Hydra outside the instance, rare spawn.
Verdan the Everliving – Living Root (staff), Seedcloud Buckler (shield). Both blue and BoP.
Deviate Faerie Dragon – Firebelcher (blue, BoP wand), Feyscale Cloak (green, BoP).
The item set found here is “Embrace of the Viper”, which means all the “of the Fang” items. The gloves are a random drop from druids of the fang only, others are BoP from bosses as listed above. It’s a leather set, mainly of interest for druids and shamans for the set bonuses, but the individual stats are ok for rogues and hunters.