To unlock the Super Hammer, you will need to complete Peach's Castle in the Story Mode. Once it is complete, you will be granted the Super Hammer which can transform Mario into Builder Mario. However, you should know that Super Hammer can only be used in the Super Mario 3D World. Once transformed into Builder Mario, Mario can build his own boxes. At one time, you have the ability to spawn five boxes with him. Apart from spawning boxes, the Super Hammer can also be used to kill enemies and destroy a large number of blocks in the game as well.