Originally posted by 1Land_1Keep
I wonder if this was included as a dev tool.
In a recent comment, one of the Arena devs mentioned having to run a whole game to automated test a card, so One With Nothing would be a good tool to force a test user to be hellbent for cards that care about that.
On MTGO they have a card that can do basically anything. I don't remember hearing about a similar debug card for Arena so they may just craft board states from scratch using the normal cards on hand.
Yup, that's what's up! I explain a bit more above.
In debug modes, we have the ability to directly cheat a bunch of effects (wish for cards, waive the mana for the thing on the stack, bounce a permanent, etc.). It has several options like that, but still leaves a lot that it can't easily do. Back in the early days, I used to have repeatedly cast & bounce Quarry Hauler to test PW abilities. Now we have a large range of debug-only cards to help with situations like this. (For example, one of them says basically "Exile target planeswalker and return it to the battlefield with 50 loytalty".)
Magic is a game complex enough that the cards can make almost anything happen, and we built the Arena rules engine to process all that complexity. So the easiest way to build new debug tools turns out to be basically creating new cards that do what you want.