Wyvern Watch

This spell is known as wyvern watch because of the insubstantial haze brought forth by its casting, which vaguely resembles a small wyvern. It is typically used to guard some area against intrusion. Any creature, within the size range specified at the time of casting, approaching within the guarded area may be affected by the "wyvern". Any creature entering the guarded area must roll a successful Will saving throw or stand paralyzed for one round per level of the caster, until freed by the spellcaster, by a dispel magic spell, or by a remove paralysis spell. A successful saving throw indicates that the subject creature was missed by the attack of the wyvern-form, and the spell remains in place. As soon as a subject creature is successfully struck by the wyvern-form, the paralysis takes effect and the force of the spell dissipates. The spell force likewise dissipates if no intruder is struck by the wyvern-form for twelve hours after the spell is cast.

Any creature approaching the space being guarded by the wyvern-form may be able to detect its presence before coming close enough to be attacked by making a Perception skill check; DC 5 in bright light; DC 10 in normal light; DC 20 in dim light; DC 30 in total darkness.