Bunny Family

Choose an opponent when Bunny Family enters the battlefield for the first time this game.

For the rest of the game, spells either of you cast
have Assist for each other, but only for generic
mana, and mana tapped to Assist taps for twice as much mana it would've produced.
When they win the game, you also win the game.

"Gotta help the family grow up big and strong!"