To get the Joker monster, you must go with Dr.Talico on his secon trip to the Kawrea Volcano. This time you'll be inside the volcano and when you start, you'll have 3 ways to go. Go all the way right and follow the path. Ignore all the small shrines that branch from the route and keep going untill your in an intersection, with a tree on the bottem path and some pillars in the upper path. Push the pillars away and take the upper path and follow it. You'll eventually come to a building that has stairs leading to the top. If Dr.Talico says its some Holy Altar Ground, your in the right place. Investigate the area untill you find the Joker's Mask. NOTE: The Joker's Mask is NOT ALWAYS there, you may have to reset the game a couple times. When you do get the Joker's Mask, combine any two monsters and use the Mask as the secret seasoning and you will get the Joker monster!