Sectumsempra is a dark curse invented by Severus Snape, which causes deep lacerations that can cause intense bleeding and even be fatal if left unattended. The curses effect is similar to the Severing Charm, except it is used for more malicious intent and causes more slash-like wounds. The name of the curse comes from the Latin words "sectum," meaning "cut," and "semper," meaning "always". The curse is not an unforgivable curse, but it is still considered a dangerous spell that should not be used lightly. When Harry Potter used the curse on Draco Malfoy, it caused deep wounds that nearly killed him. The curse is not explored heavily in the Harry Potter universe, but its uses showed exactly why that was the case.