Untamed Hatchling
Drops from Razorgore the Untamed. One of Razorgore's eggs that miraculously survived in Blackwing Lair. Dragonkin type. Untamed Hatchling will be one of the new battle pets added in Patch 5.1. It seems it will drop off of in This will be one of the pets listed in the new achievement: Information on this is here.
The Untamed Hatchling is one of Razorgore's eggs that survived in Blackwing Lair, obtained as a drop from Razorgore the Untamed in Blackwing Lair.
Guide awaiting review
Enter Blackwing Lair
Travel to Blackwing Lair and locate Razorgore the Untamed. Enter the raid and defeat him to have a chance at the Untamed Hatchling dropping.
Defeat Razorgore the Untamed
The drop rate is not 100%, so you may need to return on multiple resets. During the encounter, use the orb at the top of the room to destroy eggs while managing the adds — stepping away from the orb briefly to clear them with a quick AoE before returning to egg destruction works well.
Complete Raiding With Leashes
The Untamed Hatchling is one of three pets from Blackwing Lair introduced in patch 5.1 as part of the Raiding with Leashes achievement. Collecting all twelve pets across Molten Core, Blackwing Lair, Temple of Ahn'Qiraj, and Naxxramas completes the achievement and awards 
Mr. Bigglesworth.
Tips
The Untamed Hatchling can also be found on the Auction House if you prefer to purchase it from another player.
