A-4 Visual Tricks is the fourth Gloomy Manor mission during the Dark Moon Quest in Luigi's Mansion 2 HD for Nintendo Switch. After finding Professor E. Gadd's Dark-Light Device in the lab, you must capture the one who releases the Spirit Balls.

While it’s pretty obvious that you need to use the Dark-Light Device to find the source of the Spirit Balls, the game doesn’t offer much guidance on how or where to use it. I ended up doing a lot of trial and error and getting really confused. But in this mini Luigi’s Mansion 2 HD walkthrough, I’ll show you exactly how to find the mysterious Spirit Ball releaser and how to catch them.

Exit the lab and go north past the Common Hall. Go right and use the Dark-Light Device on the painting of a key. Collect the key and use the Dark-Light Device on the wall at the end of the hallway where there is a doormat but no door. Suck up all the Spirit Balls that appear and use the key to open the door and go to the Patio.

Go down the stairs from the porch and follow the broken path to the dirt patch at the end. Use the Dark-Light Device on the dirt patch to make a statue of Professor E. Gadd appear, then suck up all the Spirit Balls. Use your Poltergust 5000 to blow or suck the propeller on the statue's back, and another key will pop out of the statue's base. Go back to the porch and use that key to open the door to the kitchen.