How do you get the 3rd star coin on world 5 haunted house on new super Mario bros ds?

To get the 3rd Star Coin in World 5's Haunted House in New Super Mario Bros. DS, start by heading to the room with the moving platforms and the large Boo. Look for a hidden block that reveals a vine leading to a higher platform. Climb the vine to reach the upper area, where you’ll find the Star Coin. Make sure to time your jumps carefully to avoid the Boo while collecting it.