Stings

Stings are nature-based poisons that are exclusive to hunters. Like warlock curses, each sting has a different function, and many of them are useful in PvP.
 * Scorpid Sting - Reduces the target's physical critical strike chance by 50% for 8 sec.
 * Serpent Sting - Causes Nature damage over 15 seconds.
 * Spider Sting - Stings the target with potent spider venom for 5 sec, causing their next offensive spell cast to silence them for 4 sec.
 * Viper Sting - Reduces the target's healing done by 30% for 6 sec. Viper Sting is removed if the target casts a non-instant cast healing spell.
 * Wyvern Sting - Puts the target to sleep, incapacitating them for 30 sec. Damage will cancel the effect.

Removed
The following stings were removed in patch 4.0.1:
 * Scorpid Sting (hunter ability) - Reduces the target's chance to hit with melee and ranged attacks by 3% for 20 seconds.
 * Viper Sting (hunter ability) - Drains mana over 8 seconds.