Calypso, Matron of Claws

This Creature's power and toughness are equal to
the number of Rainbow Strings in play plus one.

As you cast this spell and on your upkeep each player creates a tapped Rainbow String (It's an artifact with {t}, Pay 2 life, Sacrifice this artifact:
Add one mana of any color.)

"You dare take Calypso's Rainbow String? Death! Death to you!"