Drop Block

From the Super Mario Wiki

Drop Blocks are a type of block Wario encounters during the events of Wario World. They are mostly found in the Wooden Trapdoor and Steel Trapdoor sublevels, and look like floating, green blocks. Drop Blocks are always stationed in mid-air, and when Wario steps on one, the weight causes it to descend slightly, pause, and fall quickly. If Wario is on the Drop Block when it falls, he may be forced to start the sublevel over, particularly if he's inside a Steel Trapdoor's sublevel, which has no ground. The Drop Block will return to normal position if Wario steps off it.

Obviously, Drop Blocks, like Marshmallow Blocks, must be crossed quickly.

Blocks

! Block | ? Block | ♪ Block | 4-Bros. Random Block | Arrow Block | Aurora Block | Black Block | Blue Coin Block | Bonus Block | Brick Block | Bros. Block | Coin Block | Command Block | Control Block | Dice Block | Dotted Line Block | Drop Block | Egg Block | Event Block | Expansion Block | Giant ? Block | Giant ! Block | Grab Block | Green Block | Heart Block | Hidden Block | Hint Block | Ice Block | L Block | Laser Block | M Block | Marshmallow Block | Metal Block | Minus Block | Mushroom Block | Perry Block | Pink Block | Plus Block | POW Block | Pushing Block | Rally Block | Random Block | Red Block | Rock Block | Save Block | Shine Block | Simu-Block | Spin Block | Star Block | Stone Block | Super Block | Triangular Block | Turning Block | Used Block | Warp Block | Wooden Block | Yellow Block | Yoshi Block