They are the same 37 cards that you can find in non-foil in the summer Collector Booster and include cards such as The One Ring, Palantr of Orthanc, and Delighted Halfling
This booster pack contains 36 booster packs of the Gatecrash set for Magic the Gathering
Its a win condition and a source of card advantage
Terastodon, Woodfall Primus, and Primeval Titan are probably the best cards for the "big green creature" role, but Simic Sky Swallower and Broodmate Dragon can serve the role as well, although they require greater deck manipulation to be able to hard cast should you draw either of them before finding your Natural Order
While McDonalds hasnt said it is necessarily limiting purchases of Happy Meals, it has asked that "customers think twice before placing excessive Happy Meal orders during this promotion", and that "unused food and ingredients are donated to families and communities in need"