You're going to be hearing a lot about this Garruk fellow in the coming weeks. As the face of Magic 2015, his imposing visage is going to be all over the place, looking about as intimidating as any Planeswalker ever has. Dude means business.
As Garruk stalks the multiverse for bigger and better prey, he's bound to run into bigger and bigger game...including you!
That's right, you'll have a chance to duel Garruk himself thanks to the gigantic Garruk card included in every Magic 2015 Prerelease box. Yup, every single box comes with your own oversized Garruk, ready to do battle. In fact, it looks a little something like this:

So what do you do with this guy, besides stare at him in wide-eyed terror? You play against him...or with him!
Here's how it works. One player plays his or her Prerelease Magic deck as normal. This player always goes first. Pretty straightforward. The other player, however, plays as Garruk! Garruk starts at 20 loyalty, and can activate one loyalty ability each turn.
Like any other Planeswalker, Garruk can be attacked—and if his loyalty reaches 0, he loses. But if Garruk's horde of Wolves drops the player to 0, then Garruk wins! (And no, the oversized Garruk Planeswalker card can't be returned to its owner's hand or otherwise removed—nice try.)
The oversized Garruk Planeswalker card is a key component of Magic 2015's experience design (designed by Ethan Fleischer and Gavin Verhey), but it's not the only one!
You see, every store is also getting an eight-foot-tall Garruk standee that looks like, well, this:

After your game, take a picture next to Garruk posing in a way that shows how your game went. Maybe you bested Garruk and can puff out your chest and show your dominance. Or maybe Garruk was too much for you to handle and you look deflated and defeated. Who knows what a tie would look like?
[Note: This section has been removed as the contest was ruthlessly ended by Garruk. Or it expired. One of the two.]
In short: play against Garruk, have fun, take a picture with Garruk, enter to win free axe.