Hyakiss the Lurker is a named elite venom spider in the Servants' Quarters in Karazhan. It is one of three bosses that can spawn after clearing most of the trash in the area. Hyakiss can be found stealthed in a corner.
Abilities
Acidic Fang — Inflicts normal damage plus 0 to an enemy, then an additional 500 Nature damage every 2 sec. for 30 sec. Reduces armor by 1000. Stacks up to 7 times.
Hyakiss' Web — Stuns an enemy for 10 sec.
Sneak — Puts the caster in stealth mode, but slows its movement by 50%. Lasts until cancelled.
Strategy
After engaging, 2 tanks build up threat on Hyakiss simultaneously. Make sure that the off-tank always stays second on the aggro-list, so that when the main tank gets webbed, Hyakiss goes to the off tank, instead of killing the raid. Remove the poison, it reduces armor and does nature damage per few seconds. If there is no one to remove it, the off tank should taunt her if the poison stacks too often (2-3 times), so that the MT has the chance to let the debuff run out. The stun can also be dispelled.
Loot
Patch changes
External links
Hyakiss the Lurker
Patch 8.0.1 (2018-07-17): Model updated. 
Patch 3.0.2 (2008-10-14): Health and damage reduced by 30%. 
Patch 2.0.3 (2007-01-09): Added.