The Sumatran Rat-Monkey (Simian raticus) is a creature created by director Peter Jackson for his demented 1992 zombie horror comedy Braindead (known in the US as Dead Alive). In the film's prologue, we learn that this nasty beast that lives on Skull Island - the fictionous location of the 1933 classic film King Kong.
The monkey looks more like a rat than a monkey, and its most notable features remain its wide, black butthole and its two long front nipples. It is nearly hairless and its skin colour is a brownish grey. Its nosferatu-like fingers are essentially claws and it has a suprisingly large amount of strength - easily ripping apart a Geoffroy's spider monkey in the zoo sequence.
It is brought to life in a jerky stop motion style, as a homage to veteran effects master Ray Harryhausen. In the sequence before the credits of the film, a hunter and his assistant evade the natives of the island and carry the monkey away for delivery at the Wellington zoo. The monkey, however, breaks out of its cage and bites the hunter - leaving the assistant to hack off all of his body appendages because the simian carries a virus that turns its victims into flesh eating zombies.
the World of Kong says these creatures live around the trenches of skull island where they are are prey to Giant spiders.