Tawnos' Book of Critters

{t}, Sacrifice a token creature: Put a Mana
counter on Tawnos' Catalog of Critters. This
counter's color(s) match those of the creature
that is sacrificed. (Creature colors are white, blue,
black, red, green or colorless. Each counter can be
more than 1 color.)
{t}: Add 1 mana of any color that matches 1 color
of each Mana counter on Tawnos' Catalog of
Critters.