A wyvern-shaped presence formed from mist fills the area, promising doom to those who stumble into its demesne.
Wyvern Watch is a 6th-level ritual.[PH2:217]
You place a ward in a 4-square-by-4-square area. The ghostly form of a wyvern appears in that area. Your Arcana check determines the Perception DC to notice the wyvern’s presence.
As part of the ritual, you can name creatures that can pass freely through the warded area, and you can set conditions that allow a creature to bypass the ward. Any other creature that enters the area is subject to an attack equal to your level + 4 vs. Will. On a hit, the target is immobilized (save ends). When the attack is triggered, you become aware that it has been triggered regardless of your distance from the ritual’s area. The ritual is also discharged.