Eric, Kakusareta Kage

Commander Ninjutsu {w}{u}{b}
Whenever Eric, Kakusareta Kage deals
combat damage to a player, that player may pay {3}, if they don't, target player draws a card,
target player gains 3 life, and target player
loses 3 life.
At the beginning of your upkeep, if you control exactly 17 Ninja you win the game.