King's Savior

King’s Savior is a green plant with spiked foliage and tiny yellow blossoms that can be found growing on the western shore of the Northern Forest in Serpent Isle, near mushrooms. A powerful sleep arrow can be created by treating the ordinary projectile with King's Savior, putting anyone stricken by it into an instant, deep slumber. It appears in Ultima VII Part Two.

Description
The Avatar used this method to incapacitate the tyrannical Draygan.

Trivia

 * King's Savior may be a pastiche of King's Foil, a plant that had healing properties in J. R. R. Tolkien's The Lord of the Rings.