mtg eerie cards Ultimatum • Secret Lair: An Encyclopedia of Magic (SLC) #5 Prevent all damage that would be dealt to you and creatures you control this turn by creatures. Eerie Ultimatum Price | mtg

This is such a commander staple

Customize your cards to the last detail

Assuming this means Wizards understands what its doing and wants to make things more accessible, you can also assume that you could see the likes of any random TV show, movie or gaming franchise popping in for a couple of cards

You can read my article about forever decks if you want some inspiration for what that might entail

The ability to cast it at any time while interacting with the board or temporarily countering a spell gives you a lot of available plays

That will have to be enough for this long-forgotten, but importantly groundbreaking mechanic.