The Alchemeister

The Alchemeister enters the battlefield tapped.
{b/g}{b/g}{t} Mill 3, Then choose one: You gain 3 life or The Alchemeister deals 3 damage to target permanent.

At the beginning of your end step, if The Alchemeister is untapped, you may exile it with 3 time counters on it , if you do, create a 7/7 green beast creature token with "Trample. and Whenever The Alchemeister enters the battlefield, sacrifice this creature".