Reincarnation
Reincarnation is a variant of the iconic Raise Dead spell in Dungeons & Dragons, although it has proven less popular in the wider /tg/ universe than its cousin. Like Raise Dead, Reincarnation is a traditionally Clerical spell aimed at bringing dead PCs back to life so you don't need to generate a whole new character. It also tends to be lower leveled than Raise Dead.
So, why isn't it popular? Well, Reincarnation is a real-life belief that, when you die, your soul is then reborn in an entirely new form. It could be a person of any race or sex, an animal, or a plant. So, Reincarnation the spell puts you at the mercy of the Random Number God, with the potential for "fun" varying widely depending on which edition you're playing. At best, you just wind up an entirely different demihuman or humanoid race to how you started - which could completely fuck over your character class, in some editions. At worst, you could come back as an animal, and thus be unable to play at all.
Yeah... people tend to stick to Raise Dead for a reason.