Dropper
From the Super Mario Wiki
Droppers are clams in the Wario series, which appear in Super Mario Land 3: Wario Land and Wario Land 4. They live, naturally, in underwater areas, and are named for their tendency to drop from the walls they cling to with spiked shells. Propelling upwards into their underside defeats them.
They look similar to Spinys, especially in-game.



