Slurpent is a large snake-like Yo-kai with red scales, and a yellow underbelly, with eight thin purple tongues dangling from his blue lips. He has yellow eyes with black sclera and a yellow and blue marking on its head. On his belly there is a 8-shaped brown symbol, and a blue "rattle" of the same shape is on the tip of it's tail.
Slurpent's ability is to make someone irresponsible from the touch of his eight tongues. In the Yo-kai Watch anime series, he has the power to clone others into eight different copies.
Slurpent appears as a Legendary Yo-kai starting from Yo-kai Watch 2. As a Legendary Yo-kai, one must befriend/recruit the following Yo-kai first in order to undo his seal.
Being traded:"I love making new friends! It's almost as fun as eating spaghetti! *slurrrrp*"
Freed from the Crank-a-kai (Yo-kai Watch: Wibble Wobble): "Lickety lick lick! I'm Slurpent, I lick you!"
Yamatan is a portmanteau of part of "Yamata no Orochi", specifically, the "eight branches" (Japanese: 八岐,Yamata) part and "tongue" (Japanese: タン,Tan), referencing the 8 long tongues this Yo-kai sports. Slurpent is a portmanteau of "Serpent" and "Slurp", referencing his 8 long tongues.
In the anime
Slurpent, like Venoct, could be based on the Yamata no Orochi, but while Venoct's design mixes it with the image of the ninja snake summoner Orochimaru from Jiraiya Gōketsu Monogatari, Slurpent is much closer in appearance to the great serpent. The Kojiki (a text on Shintoism and the origins of the country from the 8th century, and the oldest written record in Japanese history) describes Orochi as an enormous eight-headed snake with a bloody red belly and eyes like winter cherries, large enough that its body can lie across eight mountains and eight valleys, and plants and moss grow all over it. The number eight is a symbol of the infinite in Eastern culture, thus its recurrence symbolises the creature's immeasurable power and girth.
Slurpent is technically the strongest Yo-kai in overall stats when befriended in Yo-kai Watch 2.