The Tetris action that instantly places a falling piece as far down as possible is a hard drop.
When a player hard-drops a tetromino, the piece travels immediately to its lowest available position instead of continuing to fall gradually. In most modern versions, it then locks into the stack, allowing the player to clear lines and continue without waiting.
Hard drops are especially useful in fast or competitive play because they reduce downtime and make placements more deliberate. Players can preview the landing position with the ghost piece before committing to the drop.
A soft drop is the main point of confusion: it accelerates a piece’s descent but generally still allows the player to control it before it locks. Hold reserves a piece for later, while a ghost piece is not an action at all—it is the projected outline of the current piece’s landing spot.