Skreggat, the Ravenous

You cannot create copies of legendary spells you control or control spells named "Rat Colony" or "Relentless Rats". Protection from copying effects.

There can only ever be one Skreggat, the Ravenous under your control

Whenever Skreggat, the Ravenous attacks, sacrifice 2 other rats. If 2 rats were sacrificed this way mill 2 cards. Until end of turn, Whenever you would create a rat token, instead create those many tokens multiplied by the number of lands you milled during combat.