Varnim, The Swarmlord

Varnim, The Swarmlord enters the battlefield
with 2 1/1 black rat creature tokens.
Varnim's toughness is equal to 2 plus the
number of other rats you control.
Whenever Varnim deals combat damage create
X 1/1 black rat creature tokens where X is the
number of other rats you control.
When Varnim becomes the target of a spell you
may have another rat you control become the
new target of that spell.