Climb down the second ladder in World 5-3 to find a vase that produces an infinite supply of Bob-ombs. First, take the Mushroom Block and place it by the vase, leaving one block of space between the Mushroom Block and the vase. Next, stand behind the Mushroom Block and wait for the Bob-ombs to blow up the vase. When the vase is gone, move the Mushroom Block to the spot where the vase used to be. Lastly, go left to scroll the Mushroom Block off the screen, then scroll back to see Bob-ombs emerging from the Mushroom Block!