When in Hazey Maze, go to the cavern where the "sea monster" is. Groundpound on it's back. Walk on it's head. Wait until he goes by the double metal doors. Jump and land on the grate. Go in the doors and jump in the pool. There will be 2 stars there. One of them you need the Wario cap. You must turn metal and collect the red coins in the current. The other is as Mario. Go to the box at the back and keep pressing B until you get the star.