Credits: Realtern
Picking up a cursed item can summon a new ghost, while others are safe to collect without consequence. If a ghost loses its item, it starts to fade away and will search for another object to possess. If it finds a rideable mob (like a horse), it may “possess” it, making the creature invisible and adding a ghostly element to the environment.
While these ghosts aren’t particularly dangerous, they add a creepy atmosphere and an element of surprise, especially when you’re collecting items from the ground.