The Black Sheep, Bruno

At the beginning of each opponents draw step,
name a card type. That player reveal the top card
of his or her library as they draw it. If it's the
same card type as you named, create a 1/1
black Rat creature token.
At the beginning of your upkeep, if you have
created a rat on each other players turn before
this one, create a 1/1 black rat creature token for
each other rat you control.