They can't choose to opt out and sacrifice all of their creatures
Its not hard to engineer a situation like this, and if you do the card essentially becomes a fight spell that can also target players and planeswalkers
Each Play Booster contains 14 Magic: The Gathering cards, including 14 cards of rarity Rare or higher, 36 Uncommon cards, 69 Common cards, and 1 Land card
You have Madam Mim Fox who is the strongest of the Madam Mim cards to decimate your opponents board, Merlin Crab to add firepower to your units, Kit Cloudkicker who can bounce a lot of lower-powered characters, and even Peter Pan who can grant all of your Evasive characters Rush, enabling a lot of versatile plays
I love how flexible and powerful Ovika is, but she is expensive
After defeating him, he drops himself and Bartz's Brave Blade as rewards