The Glass Is Half Empty!

The Glass Is Half Empty! is the sole story mission of the Seaside Kingdom in Super Mario Odyssey. The mission's objective is to stop Mollusque-Lanceur from stealing all of the Sparkle Water from the Glass Tower by hitting four switches that activate fountains, which each fire a cork at Lanceur.

Layout
The mission begins at the Odyssey, with Mollusque-Lanceur draining all the Sparkle Water in the Glass Tower with a drinking straw. To stop the thief, Mario must hit four Ground-Pound Switches scattered throughout the kingdom, each requiring a different task in order to be accessed. The four switches are found on top of a tall rock pillar near the Beach House that requires capturing a Gushen to access, on top of the Lighthouse, under lava-coated water on Hot Spring Island, and at the ledge of Above Rolling Canyon.

Each switch will cause a fountain to start flowing, causing the cork that capped off each to fly off, hitting Mollusque-Lanceur. Each time he is hit, Lanceur will get progressively angrier and start to fire Spiked Shells into the water below. Once all four switches are hit, Lanceur will be knocked off the Glass Tower, starting the boss fight. Uniquely, this boss fight can take place across the entire kingdom. To damage Mollusque-Lanceur, Mario must capture a Gushen and spray the top of Lanceur's head with water.

Once Lanceur is sprayed enough times, he will explode, causing Mario to be launched to the top of the Glass Tower, landing on a cork floating on top of the water. There, Mario can collect the Multi Moon Lanceur had, capping off the mission.

Enemies

 * Goombas
 * Micro Goombas
 * Cheep Cheeps
 * Gushens
 * Maw-Rays
 * Komboos
 * Spinies
 * Spiked Shells
 * Moonsnakes
 * Mollusque-Lanceur (boss)