Haunting Room

{t}: Add {w}.
Channel - {2}{w}, Discard Haunting Room: It deals
4 damage to target attacking or blocking creature.
This ability costs {1} less to activate for each
legendary creature you control.
No, not a haunted room, a haunting room! If we
didn't gave the ghosts a place to haunt, we'd be living
in a haunted house!