Grow Huge! Edit
With the Super Mushroom, Henry is able to grow huge and become nearly immortal. This is one of many choices in Stealing the Diamond. You can find this in stealing the diamond by sneaking in, and making it to the retro room. The Super Mushroom is the only correct option out of 4. By making this choice, Henry crushes the case for the diamond and steals it, until he is shot by a guard with a cannon. He then becomes small, and sneaks out during the chaos.