Eleven Pipers Piping

When Eleven Pipers Piping comes into play, you
may either create a 1/1 black rat token or an 1/1
green elf token. At the beginning of your upkeep,
create either a rat or an elf token. All rats have
menace and when this creature deals combat
damage target player discards a card. All elves have vigilance and {t}: Add {b}{g} to your mana pool.
Eleven Pipers Piping's power and toughness is
equal to 11 times the number of Rats and Elves in
play.