Life-Binder's Handmaiden

Alexstrasza, the former dragon Aspect of Life, is known to be a kind and patient mentor. Under her tutelage, only the most dedicated pupils acquire the title of "Life-Binder's Handmaiden."

Riding Requirements:

This mount is available to all eligible characters on your account.
Level 10
Apprentice Riding (ground)
Expert Riding (flying)

Source:

Deathwing in Dragon Soul (Heroic).
The Black Market Auction House (rarely)

Introduced in:

Patch 4.3

Travel Mode:

Ground (+60% or +100% speed)
Flying (+150%, +280% or +310% speed)

Speed depends on your riding skill.

Other Mounts Using the Same Model:

Blazing Drake

Twilight Harbinger

More info on Wowhead:

Life-Binder's Handmaiden taught by Life-Binder's Handmaiden