Curious Caverns
"Curious Caverns" is an 
"Around The Island" quest that is unlocked when it has been at least one day since the player has completed the "Revive the Oasis" quest.
Quest Description
"Explore a mysterious cavern revealed by the restoration of the Oasis..."
Quest Information
The player meets with 
Pompompurin, who was enjoying the view of the Oasis and reminisces about the time his Dessert Boat was on the ground, but comments that it is better and even more 'boat-like' now that it is floating on the water. While taking a stroll, he noticed the waterfall knocked a few rocks down and urged for the rocks to be removed as they were unstable. He says that he would do it himself but needed a nap after his stroll.
Pompompurin then brings the player to the location of the Rockfall, where the player has to use their 
Pickaxe to break the Rockfall. After which, he says that they can walk through the waterfall and although he wants to take a nap, he does not want the player to be left alone. Therefore, they walk through the waterfall together.
After emerging from the waterfall, Pompompurin and the player end up in the 
Merry Meadow, where the quest ends.
