Arvinox, the Mind Flail isn’t a creature unless you control three or more permanents you don’t own.
At the beginning of your end step, exile the bottom card of each opponent’s library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.
Near Mint - $500
Lightly Played - $400
Moderately Played - $300
Heavily Played - $300
Damaged - $300
Near Mint Spanish - $500
Lightly Played Spanish - $400
Moderately Played Spanish - $300
Heavily Played Spanish - $300
Damaged Spanish - $300