Thundertrap Trainer [Bloomburrow Prerelease Promos]

Offspring 4 (You may pay an additional 4 as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.