Bombchus

Think of a bombchu as a mechanical exploding mouse. When used, Link places the Bombchu on the ground in front of him, and it "runs" forward for the duration of its fuse, on any surface, regardless of the gradient. This means a bombchu could be used to detonate a target on a wall or ceiling, or beyond a point otherwise inaccessible for a normal bomb. Just line yourself up, set the bombchu down and watch it run up the wall at that pesky rock near the ceiling. Then BOOM!