Random Card of the Day #156:
Painter's Servant - 2
Artifact Creature - Scarecrow
As Painter's Servant enters the battlefield, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.
Funny how I got the other combo piece for near-instant wins. The other piece was mentioned in RCotD #62: Grindstone.
However, this card is really only known for it's abusive cases. Which the first was mentioned above, and the second was is playing this card alongside Iona, Shield of Emeria--particularly in EDH games.
I mean there are literally dozens of cards that limit things to colors, the most popular being Doom Blade. You can see RCotD #100 for more specific closet cases if you are that interested.
A card just literally waiting to be abused. Sounds like a 5/5 if I ever saw one.