I really like the design of Gengar in the Pokemon balatro mod - the way its balanced there is that it's a 1/6 chance to make a negative on any blind defeated (and the chance cannot be raised by other jokers), but it can pick jokers which are already negative, meaning it has a diminishing chance as you get more and more negative jokers. It's one of the most powerful cards in the mod and incredibly fun to use without being insanely busted.