The GLOOM biome in PEAK is a mysterious location, and it’s filled with the spooky ghosts. If you want to obtain the Exorcist badge, you’ll need to deal with your fears and burn up the ghosts that will try to haunt you on your adventures.
How to burn up ghosts in PEAK
To burn up a ghost, you’ll need a source of fire. Once you head to the GLOOM biome, head to the swamps. This is the area that remains hidden under the mist, and it’s filled with Crows. You’ll also get consistent sleep damage when you’re in the swamps, and letting that go unchecked can be dangerous.

To burn a ghost, you need to find a Candlestick. I found one inside a piece of luggage, but their locations are completely random. Once you find a Candlestick, wait for the ghost’s sound effects (it’s impossible to miss). Activate the Candlestick when the ghost is near, and it will get the job done.
The Candlestick also prevents any sleep damage when it’s active. That’s a bonus to keep in mind if you have low health. Another way to burn the ghost is by activating a Belltower. There are five of them located on the map, and you can activate all on the same run to get the Belltower badge.
Activating a Belltower also creates a safe space in the mist for you to stand. Moreover, activating it near a ghost also helps you to burn it for the Exorcist badge. Finally, you can also use a Faerie Lantern for the same task (however, I haven’t found one yet, and I went with the Belltower route).