This has a passable baseline as a three mana 2/2 that can tap for Green, and most Green decks in this format will have enough Elves for there to be additional upside
The Enchanted variant goes for a more dynamic action pose than the standard version and, contrary to most Winnie the Pooh material, chooses to make him pop against a dark background
He gives you a bunch of information, lets you do disgusting green ramp things off of the top of your deck, becomes a giant monster....what's not to love
Heat Shimmer is great, as not only can you copy a creature for their enter the battlefield ability, but it can also combo with Dualcaster Mage for an alternate win condition
Maybe it wont end up fitting in U/W Spirits, but I certainly want to try it
Crew and saddle keyword abilities mean that youre tapping creatures to animate vehicle artifacts and to improve your mounts performance, so youre always turning a bunch of cardboard sideways in these kinds of decks