You can pay X, one red, and one green, to grant a Wolf or Werewolf you control +x/+0 and trample until the end of the turn
Only a few hundred copies of the card exist, so theyre coveted by collectors
On cards that don't get a security stamp (usually commons and uncommons), the acorn will be a printed stamp where the security stamp would have been
Obelisk of Urd isn't really exciting when it hits only one creature, but +2/+2 is a sizable bonus, and even a few creatures receiving the bonus is enough for it to matter
Interested in the hottest movers in the MTG marketplace
The good news is that most green decks in most constructed formats play Boseiju, which means if you have been playing other formats you likely have these, or if you want to branch out at some point Boseiju will be useful in other places