Mass Extinction

Flash
When Mass Extinction enters the battlefield,
destroy all lands and all nontoken creatures. Put
2 0/1 colorless Jellyfish onto the
battlefield. They have "At the beginning of your
upkeep, put a 1/1 counter on this creature.
When this creature has 3 1/1 counters on it,
sacrifice this creature."
{t} Mass Extinction deals 1 damage to any target.
"I'm too young to d..."