Boomerang
The Boomerang is an item that make its appearance in some of the e-Reader levels of Super Mario Advance 4: Super Mario Bros. 3. When thrown, the blue boomerang defeats any enemy it touches before returning to Mario, who much catch it using the B button if he hopes to re-use it.
While a few Japan-only levels featured blue boomerangs, only one of these was made available in other regions: the World-e level Slidin' the Slopes. Near the end is a Boomerang Bro. with a blue boomerang that is dropped when the enemy is defeated; the player can then pick it up and use it for the remainder of the level, though it disappears upon completion, much like the Goomba's Shoes.
There was also an e-Reader card released only in Japan that uploaded a boomerang to the player's inventory; the item worked the same way as the blue boomerangs.
