Awarded for successfully riding all mountable monsters. There are only a handful of mountable monsters in the game. They are located in the following areas:

Bee Rider / Midnight Horknight - In Laguna di Gondolia this hornet is hovering in the area. Who wouldn't want to ride a giant bee?!
Dragon Rider - You'll find this mount in Mount Pang Lai.
Face Stack Mount - Found in Snowfield of Snaerfelt is where you'll find this peculiar mount.
Headless Horseman / Red Eye Horse - In the Celestial Sands or Gallopolis area.
Perl Mobile / Eggsoskeleton Mount - On the lower level of the king's temple (King's Barrow) you will find this ominous mount (not missable).
Skeleton mount / Skullrider's Steed - You can find this mount in the Cryptic Crypt (not missable).