Baddinyan in Yo-kai Watch 2

The player has to go to the apartments in Shopper's Row, where Roughraff and Coughkoff are arguing over who is spikier. To obtain Baddinyan, the player has to speak to Roughraff and say he's the spikier one. He will then fuse with Jibanyan to form into Baddinyan, the fusion breaking apart after Baddinyan gives the player their medal. Note that, this encounter is unlocked during Chapter 3 "School Is Strange" in the main story.