Shadowverse

And there’s already a follower who summons such a button after death – his name is Leonidas.

I still remember playing against Neyra, and since I didn't read the card descriptions, I even killed this Leonidas myself, reasoning that "it's unlikely that the end of the world will come after his death, and I can't tolerate an extra body on the board."

Added 7 minutes later

No, that's not what I meant at all, damn it. Not in one turn. To get the win button, you'll have to kill him a hundred times. Almost like a seraph, basically, only a follower and not quite as overpowered.

Well, if he drops into your hand right away, that's going to be a real pain. You draw him in the mulligan, and then you play him every turn when he dies, and when he doesn't die, you clear the board with him, and he still dies, and on the tenth turn you win. But if he disappears into the deck, then the card is completely unplayable.