"Choose a Color" effects

[Gorzo]

If you activate an ability like that on, say, {Crosis, the Purger}, is "colorless" a valid option, or are you limited to the five options of "White, Black, Red, Green, Blue?"

[BadLuckIrish]

If you activate an ability like that on, say, {Crosis, the Purger}, is "colorless" a valid option, or are you limited to the five options of "White, Black, Red, Green, Blue?"

Only one of the 5 main colors. Colorless is not a colored. Pro-colored can still be affected by artifacts

[Gorzo]

If you activate an ability like that on, say, {Crosis, the Purger}, is "colorless" a valid option, or are you limited to the five options of "White, Black, Red, Green, Blue?"

Only one of the 5 main colors. Colorless is not a colored. Pro-colored can still be affected by artifacts

Thought as much, forcing someone to pitch all artifacts and lands in hand would have been too good to be true.