Old Crone

Companion — The text of each nonland card in your starting deck contains the word "exile".(If this card is your chosen companion, you may cast it once from outside the game.)
When Old Crone enters the battlefield, select a card from your sideboard, then exile it. (It is now in the game.)
"Forget she there / 'Slike she gone / 'Til she 'ppears / Like a neeper's fawn." — Gahguleine