Rat Summoner

At the beginning of your upkeep create a 1/1
rat token with deathtouch. Rats you control have flash. Whenever this creature attacks create five 1/1 rats with deathtouch tapped
and attacking. Exile them at the end of
combat.
{t}: Create a 2/2 rat token creature with
"{1}, {t}: Create a copy of this creature."