As an additional cost to cast Mageta's Charm, sacrifice a Plains.
Choose one – Return target equipment from your graveyard to your hand; or each player sacrifices a non-Legendary creature; or prevent the next X damage to yourself this turn, where X is equal to the number of lands you control on the battlefield and in your graveyard.
Instant
For Challenge # 081. I liked Jolrael's Charm and figured I'd round out the cycle. Hey, ho, Mageta.
I'm pretty sure that if I didn't mention it first, someone else is bound to tell me that Innocent Blood is black. And it is. Though, I'm not really sure why. It's kind of like a mini-Balance. Doesn't white get Balance effects?
I added it anyway because I like how the 'sac a non-Legendary creature' feels like Mageta's ability. It's probably too cheap... but sacrificing a land in the early game to stop a 1/1 from hitting you is a terrible idea. And later in the game, when you have enough lands in play, you're likely to 3-for-1 yourself just to get rid of... a 1/1.
Returning an artifact was added because I like the symmetry of "sacrifice one thing, get one thing back". It couldn't be a straight up artifact, though. Mageta hands out swords in Mageta's Boon.
I want at least one of the abilities on each of these cards to point at your land being sacrificed. Originally, I planned for that last ability to gain life, but I couldn't get over how much better than a certain 5 casting cost common green sorcery who's name escapes me right now. Preventing a perfect amount of damage is a lot more situational, though, so I figured that would work.