|First appearance||The Return of Tsul 'Kalu|
It inhabits mountains of Himalayan china. These small apes are thought to be a subspecies of orangutan or large relative of the golden-faced apes.
At the end of The Return of Tsul 'Kalu, Argost stole this cryptid from Doyle, who was mistakenly trying to protect the owner, thinking Argost was after him instead. It was originally thought by Doyle to be a Yeti, the cryptid that killed his and Drew's parents, although it was later revealed when they raided its former mountain home that Argost was the Yeti, and had lived with it before he had gone out into the world. In those days, Argost had been the one stealing from human camps and murdering the visitors, which prompted the local monks to make unsuccessful attempts to capture him. Along with Argost, the cryptid learned English from a stolen television set, and tried unsuccessfully to convince Argost to stop stealing and murdering, knowing that it would attract attention to them.
It is unconfirmed what happened to the Xing-Xing after Argost kidnapped it, given that he and Argost were old associates, although it is possible that he was murdered to stop any potentially valuable information on Argost's past being revealed.
The Xing-Xing is a Japanese mythological sea creature known for liking alcohol, it's also the Japanese and Chinese names for the orangutan.