The Small World

Whenever a creature power 1 or less enters the battlefield, you may pay {g}{g}. If you do, reveal the top four cards of your library, put a creature card with mana value 1 or less among them into your hand and the rest at the bottom of your library in any order.
"The small creatures are welcoming, but they've learned from centuries of survival how to defend themselves. Be forewarned, what they lack in size they make up in numbers." — G