Now, ghost matters are invisible (please nevermind the lasers), so these cairns are also invisible:  But, it becomes visible when we attack it (attackable itself is correct):  After that, it keeps visible: 
Now, ghost matters are invisible (please nevermind the lasers), so these cairns are also invisible:

But, it becomes visible when we attack it (attackable itself is correct):

After that, it keeps visible:
