Like most Pokmon cards, the value of Xerneas depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Mega Evolution)
6 Gruff Triplets Expensive beaters in Limited are often vulnerable to cheap removal spells, but hexproof and indestructible aren't always green's solution for protection
A slight difference, since reanimation is so easy in pauper, but one that is worth taking note of
I stuck as many copies as I had of each of these cards in my deck and filled out the rest of the 60 cards with as many other ducks as I could find: Daisy Duck Isabel, Scrooge McDuck Miserly Ebenezer, and Gosalyn Mallard Curious Child just to name a few
Interestingly, every card in its evolution line carries this move, making it incredibly easy to stack damage