Format:
cast 'squeaky floors' room              cost: 25 mana

   The squeaky floors spell is a form of protective ward used by clerics to
warn against people entering a given area.  When the spell is cast in a room,
the floor becomes an alarm clock, waiting to be triggered.  When anyone else
enters the room, the alarm is set off, and the room utters a loud wail that
can be heard a long distance away.

Note that this spell cannot be cast on rooms without solid floors, such as
in the middle of a pond or hovering in the air.