Here are a few options: Leave the physical card outside the game and use a labeled substitute card for while the card must remain hidden in your library or face down Sleeve your deck with fully opaque backs like Dragon Shield Matte sleeves
If it weren't for the flavour text portion, it seems like it could be from a real card
Honestly, Arena is the reason I've gotten into Magic in such a big way
The set is available for preorder now from your local game store, online at retailers like Amazon, and elsewhere Magic: The Gathering products are sold.
[the card types are Artifacts, Battle , Creature, Enchantment, Instant, Land, Planeswalker, Sorcery.] The mechanic was then previously teased in the current expansion of MTG, Phyerixa: All Will Be One, where the lead designer of MTG, Mark Rosewater, that the Battle mechanic will be featured in MOM
If you throw in a way to distribute poison counters like Infectious Inquiry or Prologue to Phyresis, theres another angle of attack right there