Yo-kai Watch Wibble Wobble
Dracunyan was part of an early Wibble Wobble event. He was unlocked only after you completed a certain mission. His Soultimate move was also upgraded by completing certain tasks. It is unknown if he is availble via other means, like the Crank-a-kai machine.
To unlock Hidden Stage 8 and Bananose in Shopper's Row you must link 20 or more Wib Wobs on Stage 100. The easiest way to do this is to use Dracunyan who can convert Wib Wobs into himself. Bananose is pretty easy to friend, just make sure you stock up on lots of Candy Apples (520y) in the Shop.