The first star of this course will require you to be on Huge Island, but considering its location, it’s best to start out on Tiny Island first. Once you spawn in and can control Mario, Long Jump to the platform to the left of your starting point. This will have a yellow box with a 1-Up inside, as well as a Keronpa Ball. From there, you will want to continue by Long Jumping to the next area with the pipe, making sure to watch out for the Piranha Plant that can spawn, as it shoots fire and the area isn’t exactly the best size for a frantic Mario.
Jump in the pipe and you’ll be switched over to Huge Island, in the same area as before. Note that this area is a bit damp, so your jumping ability will be limited to both a single jump and height. On this patch of land, there will be five Piranha Plants, which are a lot bigger as Tiny Mario. Your goal is to defeat all five of them and thankfully, it still only takes a single attack to bring one down. Once you defeat all five larger Piranha Plants, the star will spawn.