22 Sept 2011
A multicolored creature with intimidate can be blocked by any creature that shares a color with it, in addition to artifact creatures. For example, a white-blue creature with intimidate can be blocked by white creatures and/or blue creatures, no matter what other colors they are.
22 Sept 2011
If an attacking creature has intimidate, what colors it is matters only as the defending player declares blockers. Once it’s blocked, changing its colors won’t change that.