Serpensortia is the incantation for a spell which causes a large serpent to burst from the end of the caster’s wand.
References from the canon
- Draco cast this spell on Harry at the Duelling Club on Snape's suggestion; the serpent moved to attack Justin Finch-Fletchley (CS10).
- According to The Book of Spells, "for reasons that are still not fully understood ... two categories of creature are easier to create from nothing than any other: birds and snakes." The spell to create birds is called the Bird-Conjuring Charm, which suggests that Serpensortia might be called the Snake-Conjuring Charm.
"serpens" L. serpent + "ortus" L. past participle of "ortir", to come into existence (or second segment could be derived from "sortir" Old Fr. to go out) (thanks to Jake Downs for suggesting we look at "ortir")
In the CS film, Lockhart uses the incantation "Alate Ascendare" to try to remove the snake, while in the book Lockhart silently sends the snake flying up into the air (CS/f). "Alate" means "winged" and "Ascendare" means "to climb or ascend" into the air.