If the damage is greater than the Pokmons HP, that card must be discarded
Its reportedly incredibly hard to grade thanks to manufacturing issues, and very few cards of this incredible quality can be found out in the wild, especially according to BGS standards
It works well with token making strategies that make small dorks like the 1/1s you see with Soldiers, Squirrels, Goblins or Saprolings
And then you can play out a bunch of elves and win with something like Craterhoof Behemoth, or typal lords like Elvish Champion and Elvish Archdruid buffing all your creatures
However, if you control your commander as you start casting Ancestral Communion but don't control your commander by the time you finish casting it (perhaps because you sacrificed it to activate a mana ability), Ancestral Communion's first ability won't trigger
Becoming the monarch lets you draw an extra card at the start of your end but it can be taken away if an opponents creature deals combat damage to you