2019-07-12 : In the Commander variant, the color identities of cards are determined as the game begins. Changing the colors of a player’s commander doesn’t affect its color identity or the cards that can be legally included in the deck.

2019-07-12 : The target creature has only the colors Scuttlemutt gives it—Scuttlemutt’s ability overwrites any previous colors the creature had.

2019-07-12 : You must choose one or more of the five colors of Magic while resolving Scuttlemutt’s last ability. You can’t choose “artifact,” “colorless,” or “chartreuse.”