The most violent and destructive storms in Femeref occur on cloudless days.

Stampeding Wildebeests

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
At the beginning of your upkeep, return a green creature you control to its owner's hand.

Duel Decks Anthology: Garruk vs. Liliana

Trample
At the beginning of your upkeep, return a green creature you control to its owner's hand.

Duel Decks: Garruk vs. Liliana

Tenth Edition

Prayers for rain are answered with the thunder of hooves.

Visions

Trample
During your upkeep, return a green creature you control to owner's hand.

The ability that returns a creature doesn’t target anything. You can return a creature with shroud or protection from green, for example. You don’t decide which creature to return until the ability resolves. If you control no other green creatures, you must return Stampeding Wildebeests itself.

You choose a creature and return it all during resolution of the triggered ability. This means that if you have two Wildebeests, there is no way to end up returning only one creature.