Stone of Rats

When this artifact enters the battlefield create a
token copy of each rat on the battlefield under
your control. Whenever a rat enters the battlefield create a token that is a copy of that rat under your control. When this artifact leaves the battlefield
you lose all rat tokens created by Stone of Rats.
Rats you control have +2/+2, hexproof, trample, deathtouch, lifelink, and doublestrike. Whenever
a rat you control leaves the battlefield put two
+1/+1 counters on each rat you control.