It still happens simultaneously in game rules, and thats why you wont lose, but Arena works in two steps
In theory, with a Naban, Dean of Iteration on the battlefield, you only need half the number of blue mana symbols on the battlefield to make Master of Waves good (for example, in the worst-case scenario where you have just a Naban, Dean of Iteration and a Master of Waves, you'll still end up with 10 power across five bodies, which is a pretty reasonable deal for four mana, and if you throw just one other Wizard into the mix, things cat get out of hand really quickly when Master of Waves' enters-the-battlefield trigger is doubled)
I decided to add a surprise Pokemon inside each one as well, and I think it will be exciting for the kids to see who they got when the break it open
For the first time, purchasers will also unlock card styles for the cards in MTG Arena and the usual Secret Lair Sleeve Unlock