Eighth plague of Egypt, Locust

Flying, haste
At the beginning of your upkeep create a token
that's a copy of Eighth plague of Egypt, Locust.
Sacrifice Eighth plague of Egypt, Locust :
Counter target spell. If that spell is countered this
way, exile it instead of putting it into its owner's graveyard. You may play it without paying its
mana cost for as long as it remains exiled. (If it has
X in its mana cost, X is 0.)