Vyn, the Viscount of Valencort

Roving
Vyn, the Viscount of Valencort roves if able.
Whenever Vyn attacks, you may sacrifice X
Treasures, then gain control of target creature
with mana value X until end of combat. It is attacking the same player or planeswalker as Vyn.
Exile an artifact card or land card from your graveyard: Create a Treasure token.