Games with interesting a unique magic systems

I'm looking for games with cool spells and magic systems, the two games that come to mind that fit this description for me are Morrowind and arx fatalis, I love the spell crafting in Morrowind, fooling around with effects, strength, making game breaking spells; and the very unique and interesting system in arx fatalis, where you have to draw the runes to invoque the different spells, and how unlocking more runes, results in new spells, what other games could you all recommend that have similarly interesting magic mechanics like these?