Final Course: Corona Mountain
Corona Mountain is the final stage in the game and can be accessed once Shadow Mario has been defeated in every level. When you re-enter Delfino Plaza, you'll discover that the whole place is flooded. Shadow Mario is waiting for you in front of the entrance to Corona Mountain. Race over and follow him into the opening of the mountain.
The lava and spikes in Corona Mountain will kill Mario instantly if he touches them, so be careful. Make strategic use of FLUDD's Hover Nozzle and dodge the spikey platforms. Spray the flaming platforms with water to cool them. Continue to hop across the platforms until you make it to the solid ground again. Use the sprinkler to replenish FLUDD's water tank and break the crate nearby to net another 1-Up Mushroom. The next portion will see Mario steering a small boat to get to the other side.
Shoot FLUDD's water in short, controlled bursts to steer the boat. If the boat touches anything, it'll sink. Shoot a stream directly ahead of you if you want to come to a stop. Once you clear the pillars in the lava, ditch the boat and hop onto solid ground. Grab the Rocket Nozzle out of the Red Nozzle Box for the final portion.
Using the Rocket Nozzle, shoot yourself up and land on the clouds as you get higher and higher, The Rocket Nozzle uses a lot of water, so make sure every jump counts. Once you make it to the black Cloud, you'll discover Bowser and Bowser Jr. relaxing in a hot tub with Princess Peach.
Bowser's floating hot tub has five points marked with a flame. Run around the tub and rocket blast over the marks and crack them with a super ground pound. Doing so will rock the tub and that corner will begin to come apart. Quickly jump back to safety and repeat four more times. Once you defeat Bowser, you'll earn a Shine, and the end-game credits will roll.
