Kalain, Reclusive Painter [Dungeons & Dragons: Adventures in the Forgotten Realms]

When Kalain, Reclusive Painter enters the battlefield, create a Treasure token. (It's an artifact with "T, Sacrifice this artifact: Add one mana of any color.")
Other creatures you control enter the battlefield with an additional +1/+1 counter on them for each mana from a Treasure spent to cast them.