Big Bob-omb on the Summit is the first mission in Bob-omb Battlefield. King Bob-omb will only spawn if the first star in the star select is selected.
Tips
To kick up slopes, press B while holding down A.
Push against the wall at the other side of the warp and return the control stick to neutral to warp quickly. Be sure to release the stick after pushing against the wall, otherwise Mario will bonk.
To get up to the warp with four wallkicks, hold neutral during the wallkicks and make sure you're holding A as long as possible. Tapping A will result in a small wallkick with less height. Try to avoid getting a firsty on the first wallkick, as it will make timing the second wallkick more difficult.
