"Watch out! Ghosts can appear and disappear when chasing you. They can also fly, so being on high ground isn't as useful. Ghosts deal 10 ~ 12 damage per touch. They have a walkspeed of 18, so they can outrun you if you don't have a speed gear. Hiding inside or behind cover would be another option to survive!"
"Comparing to standard Ghosts, they deal 13 ~ 15 damage per touch with a walkspeed of 24. They also stay invisible longer."
Permanently invisible, move faster, and deal more damage.