Gook (グック, Gukku) is a lazy Shinigami.
Gook's most prominent feature is his animal mask which is that of a cattle skull. He also wears a big green beaded necklace and has yellow eyes.
Like Deridovely, he enjoys gambling too, although he is a poor gambler.
He appears gambling with Deridovely in the first episode and witnessed the way of Ryuk to the Human World. Thereafter, it was absent from the series, and only appeared in the Ryuk's flashbacks in which he had to Light on the Shinigami Realm.
Gook also appeared in the prologue chapter Death Note One-Shot Special. He thinks that Ryuk is the Human World but is mistaken, and that was who was Midora. After that he starts chatting with Ryuk on apples that Midora brought the Human World to Shinigami King in exchange for a Death Note but Gook does not care for it.