Advertisement Its kind of incredible this card is black border and not from an Un- set
It doesn't enter prepared, but there's a way for it to resolve on the battlefield prepared, thanks to an added ability
While I cant find anything confirming why this is, its likely because its on the Reserved List, so Wizards is hesitant to errata something they cant reprint
Similarly, when Fairy Godmother Mystic Armorer from the Rise Of The Floodborn pack is in play, the strength of all your characters in play increases by three points, and if this card is banished, you get to return it to your hand, not the discard pile
Its possible he could come down and take out an Elspeth and run away with the game, but what is far more likely is that he makes a 3/3 deathtouch then eats a Heros Downfall or Banishing Light or Detention Sphere or Dreadbore or [Khans PW removal spell]