What is the only spell known to repel a lethifold?

The only known spell to repel a lethifold is the Patronus Charm. The Patronus Charm is a powerful defensive spell that produces a magical guardian in the shape of an animal that is able to repel Dementors and other dark creatures. When cast against a lethifold, the Patronus Charm creates a powerful barrier that the lethifold cannot pass through. However, successfully casting the Patronus Charm requires a strong positive emotion and great mental focus, making it a difficult spell to master. It is recommended to have a strong Patronus before attempting to repel a lethifold, as failure to properly cast the spell could result in being consumed by the creature.