Nevinha, the Broken Hamster

Companion — Your starting deck contains only
mythic rare cards and land cards. (If this card is
your chosen companion, you may cast it once from
outside the game.)
When Nevinha, the Broken Hamster enters the
battlefield, choose a card you own form outside
the game that is banned in a Constructed format,
reveal that card, and put it into your hand.
"Soon I'll be a Elk!"