Grove of the Dreampods

When you planeswalk to Grove of the Dreampods and at the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
Whenever chaos ensues, return target creature card from your graveyard to the battlefield.

March of the Machine Commander

Planechase Anthology Planes

When you planeswalk to Grove of the Dreampods or at the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
Whenever you roll {Chaos}, return target creature card from your graveyard to the battlefield.

Planechase 2012 Planes

When you planeswalk to Grove of the Dreampods or at the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
Whenever you roll chaos, return target creature card from your graveyard to the battlefield.

Both abilities are mandatory. You must put the creature card onto the battlefield, even if you don't want to.

If you don't reveal any creature cards from your library, you'll put the cards from your library on the bottom of your library in a random order. Essentially, this will shuffle your library, although you are not shuffling it for purposes of effects that care about a player shuffling a library.