Guil is a brown animatronic tabby cat with a movable tail that can move back and forth. His eyes are green in color, but his eyes disappear during the night, leaving the endoskeleton eyes visible. He wears a cooking apron that reads "I Love Freddy Fazbear's Pizza" with a heart-shape instead of the word "love". Like Foxy, his teeth are also sharp. He is also shown carrying a tray.
In his first prototype appearance, his endoskeleton tail is visible, possessing a broken right eye, several holes on arms and apron, and a damaged jaw hanging open with couple of wires attaching to his endoskeleton mouth.
Guil first starts in the Kitchen during night. The only two locations Guil appears are Show Stage and West Hall.
Every time when he moves to different locations, he makes a very deep and demonic laughing sound. Like Chica, Guil goes near the Office at the East Hall. However, unlike Chica, he appears in the doorway, very much like Bonnie.
When Guil is in the Office while the player is viewing the cameras, he makes a loud, scratching noise sounding as if he were scratching on metal. Once the player lowers the camera view and returns to the Office, Guil attacks them and ends the game.
- Guil could be inspired Crusty the Cat, a retired animatronic from Chuck E Cheese's.
- His toy counterpart for the pizzeria's second prototype was considered, but ultimately scrapped while Toy Guil's endoskeleton still exists.