The Sleep Hex (somnium) is a spell. This spell is a fundamental part of the First Year Army Battles, as it is used to simulate soldiers getting taken out by enemy fire somewhat safely. The spell is extremely weak and can be blocked by virtually anything. Trinkets or garments that block minor jinxes and hexes (or even regular garments with sufficient fortitude such as chain-mail) easily stop this spell, as well as even the weakest shield spell, Contego. However, it requires a minuscule amount of magic to use and it is invisible, making it an asset for combat. Unlike other spells such as Stupefy, the power of the Sleep Hex does not amplify if hit with multiple Sleep Hexes at once, making it safe to mass-fire. This allows armies to shoot down enemy soldiers without fear for safety. It is unknown how long one stays unconscious when struck with the spell, and it is also unknown what the countercurse is, though it may just be a lower-power Innervate than for something like Stupefy.