If you're casting this before going off, you're going to cast 6-7 more spells, so lose 6-7 life. If you fizzle, you're most likely just dead as you don't get a second chance. You'd need to run more bounce spells than usual to mitigate that.
For that much life and mana, I think I'd rather cast Infernal Contract, it's better in multiples and you know the cost when you play it.
Also, the artwork makes me think of Michael Jackson.
This doesn't work well with either Chain of Vapor or Teferi but kinda works with PO, meaning that you can target this with PO this just to sacrifice it. I don't know it this makes it better than Night's Whisper in PO lists that want it, but I don't even see PO with Whisper right now, so idk. And with Underworld Breach coming, I doubt black will be the better color for those kinds of decks right now.