The first one I generated was a 1/1 creature costing 1 black mana, that had the ability "if you control 8 or more lands during your upkeep you win the game". It's been a while since I've played Magic, but that seems a little overpowered to me :)

Not far off these days. Might not see play in most formats. Would be cool in standard or limited though.

Too weak in modern, basically like any other bomb in limited but less interesting, and too non-interactive in standard.