Harry Potter spells (S-Z)

Slugulus Eructo (Magic-User 1)
Casting time: 1 segment
Range: 60'
Duration: 1 round/level
This spell causes the victim to begin vomiting up slugs at an alarming rate of 10 slugs per round. Each round they must make a save vs. poison to be able to act at all, and if they do they will be at a -5 penalty to most rolls. The size of the slugs is proportional to the size of the target, and also they might be affected in other ways, like you could make a wraith throw up intangible slugs that drain levels from cauliflowers.

Switching Spell (Magic-User 3)
Casting time: 1 round
Range: 30'
Duration: 1 round/level
Causes two creatures or objects to have their appendages switched. For example a person could have their ears switched with the spines of a cactus, or a dragon could have its teeth switched with those of a horse.

Unbreakable Vow (Cleric 3)
Casting time: 1 turn
Range: Touch
One person gives terms of a Vow to another person, who accepts the vow of their own free will. The spellcaster then casts the spell upon them and the vow becomes unbreakable; if the vow is broken, the one who made the vow will die instantly. (No, your henchmen will not let you cast this on them.)

Other well-known spells:
Sectumsempra 'Magic Missile' (not exactly the same, but close enough)
Silencio 'Silence'
Specialis Revelio 'Identify'
Stupefy 'Power Word, Stun'
Tarrantallegra 'Otto's Irresistible Dance'
Vulnera Sanentur 'Cure Critical Wounds'
Wingardium Leviosa 'Levitate'