Walkthrough: After grabbing the Multi Moon from the stew, the volcano will explode and bring Mario back to the Odyssey Airship. Unfortunately, you will have to make your way straight back up the volcano in order to battle Cookatiel, this time using the western path up it. Start by going behind the airship and looking for some Valbonans in the wall. Mario can use these with the help of Cappy to get to the roof and bypass the area now covered in lava, dropping down afterwards next to the corn cob wheel and then using Cappy once more to capture a Lava Bubble.
As the Lava Bubble, head head up the left side to find a new cannon that can be used to launch Mario across the gap to a cliff he can climb. Watch out for the Fire Bros after you do, the same that will send Mario screaming if their fiery attacks make contact with him. Once at the top of the cliff, use the warp pipe to go into the next 8-bit mural. Inside this mural will be a Hammer Bro, one that can easily be defeated simply by waiting for him to to jump on the top ledge and then knocking the block out from under him. Once outside the mural, cross the corn cob log to head inside Volcano Cave.
Once inside Volcano Cave, capture another Lava Bubble and make your way up the slope while yet still dodging falling logs. If you'd like, check the sides of the slope to find some more Purple Coins. Once you reach the top of the hill, drop down to the other side using the given pillars of lava. As you do, use your camera to spot a hidden cave behind you that holds a Power Moon. Once you reach the final platform, capture and use another Lava Bubble to light the unlit torch, earning yourself another Power Moon.