Here's a short list of what ghosts are capable of in my game's fiction, do with it what you will.

• Possess other people, and possibly make them do something (depending on the ghost's cognizance)
• Freeze things, possibly solid if the ghost is powerful enough
• Possess a Husk to then become a Vampire (HIGHLY dangerous, with many far reaching consequences)
• Possess and possibly manipulate Hulls
• Become invisible while doing other things
• Interact with objects remotely, such as snuffing out lights or opening locks
• Pass through normal objects like walls and doors, no matter how thick
• Can literally float and fly
• Carry certain objects, depending on weight and magical influence (somewhat unreliable)
• Speak about their memories of the past, whatever might remain
• Interfere with sparkcraft gadgets and security
• Generate electroplasmic lightning (rare, but possible)