The latest GW2 Game update Back to School introduces new Mini Pets Super Raccoon, Super Yeti, and Super Banana. A three-pack of minis from Super Adventure Box World 2 is available in the Minis category for 500 gems. Combine them with a continue coin (purchased from Moto outside the Super Adventure Box) in the Mystic Forge to receive the special Mini Super Assassin. Available until September 30.
You can also buy a Mini Moto for 20 baubles.