Nehdyah, the Color Drainer

Indestructible
As long as your devotion to colorless is less
than 5, Nehdyah isn't a creature.
Whenever an opponent casts a colored spell put
2 +1/+1 counters on Nehdyah.
{4}{t}: Choose a color, until the end of your
next turn players can't cast spells of the
chosen color.