mtg beacon cards Beacon, Set Name: Fifth Dawn, 17 From the Fifth Dawn set. MTGNexus - Meridia's Beacon

1 Crosis, the Purger

This is preselling in the $7-$8 range, and I can immediately see it hitting sideboards against those pesky decks that play four copies of Hopeless Nightmare

Use Mind Over Matter to untap Mikokoro, Center of the Sea and then use your infinite mana to use Mikokoro, Center of the Sea again

Most decks need a combination of Lockdown and another hate piece, like High Noon or Authority of the Consuls, to truly put Prowess in check

If your opponent(s) do decide to go the route of trying to find items to hide though, you can choose to just hide cards from your deck and if you want to be really fancy, claim something like "I'm hiding red blood cells