Twitch, Shadowy Step

Whenever a Rat enters the battlefield under your control or a Rat you control deals combat damage
to a player, put a cheese counter on Twitch.
Remove X cheese counters from Twitch, gain
control of a creature or artifact with converted
mana cost X.
Remove 3 cheese counters from Twitch, draw a
card from an opponent's library, you may pay
mana of any color to cast it.