Never Ending Swarm

Trample, Menace
Never Ending Swarm enters the battlefield
with {x} +1/+1 counters on it equal to the
amount of mana spent to cast it.
{t}Add {c}{c}. When you next cast a Hydra
creature spell with {x} in its mana cost or
activate an ability with {x} in its activation
cost this turn, copy that spell or ability.
You may choose new targets for the copy.
(A copy of a permanent spell becomes a token.)