Shrink Cap

The Shrink Cap is an unused and unfinished cap item in Super Mario 64 which appears as a tiny version of Mario's regular hat, which when put on causes Mario to shrink to a quarter of his usual size. In this state, Mario is just as vulnerable to damage as if he were wearing no hat at all. While his hitbox is reduced to match his visual size, he still interacts with level collision as if he were full size. It is likely that this was intended to be modified as well, but the item was scrapped due to the complexity of implementing this feature in the game's engine. The concept behind the Shrink Cap can still be seen in the course Tiny Huge Island, which uses two copies of the level at different scales to achieve a similar effect.