Gu-ku (グーク) (commonly called Gook) is a duck-like pet similar to Poogie that was first introduced in Monster Hunter Frontier Season Forward 1. Its costume can be changed just like a Poogie, and it apparently has its own pond. As of Frontier's 4th Anniversary, more costumes were introduced.
- In Mezeporta Square, a Gu-Ku can be seen readying up and setting out for a quest.
- Since Forward 5.0, a hunter is allowed to have a maximum of five Gu-Ku.
- If a Gook is left without attention for long periods of time, it will eventually leave the hunter.