Drill Bros.

Baby Drill is a technique used by Baby Mario and Baby Luigi in Mario & Luigi: Partners in Time. The babies learn this technique shortly after they receive their hammers in the Vim Factory. It is taught to them by the Hammer Bros., and allows them to burrow underground - avoiding enemies and allowing them to slip under the tightest spaces. The babies cannot dig through hard materials (such as metal), and receive a Bean if they surface on an 'X' marked spot. If they surface on an enemy, the overworld enemy is stunned, which allows the babies to either escape or engage the enemy more easily.

The technique returns in Mario & Luigi: Bowser's Inside Story under the name of Drill Bros. It is usable by Mario and Luigi and serves a similar function to the last game, letting them traverse under tight areas and find Beans in the overworld, marked with again an 'X'. The Baby Drill appears in volume 36 of the Super Mario-Kun. Rather than using it as a technique for digging up beans, the Baby Mario Bros. use it as an offensive attack. They use the move to attack Swiggler, Mrs. Thwomp, and even the adult Mario Bros. The babies' positions also alternate, unlike in the game, where Baby Luigi is always on the top. The babies also do not require hammers for the move in the manga.