It's a BaB promo, so unsure if its even actually in packs of the set. And even if it is, the promo could just have the Mythic rarity while the set version does not.
Oh hey, I already have 4 foil Mana Confluences blinging out the deck I’m using them in, but I welcome and will find a place for this different art work Mana Confluence. Going to pick up this in maybe a playset of foils.
Here is FB page: https://www.facebook.com/TabletopsHobbiesandGames/
Oh, it’s a buy-a-box.
Do love that art and flavor text, at least!
: D