Release the Gremlins

Oracle Text

Destroy X target artifacts. Create X 2/2 red Gremlin creature tokens.

Card Rulings

2/9/2017 The value of X is limited by the number of artifacts that you can target. You can’t target the same artifact more than once.
2/9/2017 You can target an artifact with indestructible. It won’t be destroyed, and you’ll still create X Gremlin tokens.
2/9/2017 If an artifact becomes an illegal target for Release the Gremlins, it won’t change the number of tokens created. However, if every target artifact becomes an illegal target, Release the Gremlins doesn’t resolve and no tokens are created.