An item that puts a horible curse on the victims of its spell.
A dark emperors gloves that make an excelent weapon and torture tool.
Elementalist have commonly used jems to further their powers over nature.
Magic should have side effects, both expected and unexpected - fortuitous and deplorable. Expected side effects add anticipation, while unexpected ones increase the drama of the scene. The result can be comedic or dire, it dpends on which circumstances work best for your game.