Bertilak de Hautdesert

When this card transforms, your opponents may choose to give you a treasure. For each opponent
who doesn’t, you may deal 5 damage to any
target.
Treasures you sacrifice for green mana produce
two mana of that color instead.
Then the great man in green gladly prepared him,
gathered up his grim tool there to smite -Sir Gawain
and the Green Knight