Infinite Timereaver

Fickle and savage, these drakes slip in and out of time until they find a worthy rider.

Riding Requirements:

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

Source:

Any Timewalking Dungeon Boss.
Only available during Timewalking
Reins of the Quantum Courser (chance)

Notes:

This armoured infinite drake is a rare drop from any Timewalking dungeon boss during any of the Timewalking events. Check your in-game calendar for the next event period.

Introduced in:

Patch 6.2.3

Travel Mode:

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

Speed depends on your riding skill.

Matching Companion Pets:

Infinite Whelpling

More info on Wowhead:

Infinite Timereaver taught by Reins of the Infinite Timereaver