This article is related to a game, manga series or other media that has not been released outside Japan. The coverage here may differ from what it would be in an official translation.
The Pickaxe (Japanese: ツルハシ) is an item in Densetsu no Starfy. During the events of Sunken Ship, a wall closes in, blocking Starfy from Moe. Starfy earlier found a Scoop, but it wasn't enough to break through the wall.
Returning to the room where Starfy previously found the Scoop makes some pillars descend, revealing the Pickaxe. After obtaining the Pickaxe, it seems the Pickaxe isn't powerful enough to break through the wall either, so Starfy searches for something else.