2016-07-13 : For more information on double-faced cards, see the Shadows over Innistrad mechanics article (http://magic.wizards.com/en/articles/archive/feature/shadows-over-innistrad-mechanics).

2016-07-13 : The power of the blocking creature and that of Howling Chorus are compared only at the moment that blockers are chosen. Changing either creature’s power later won’t cause Howling Chorus to become unblocked.

2016-07-13 : The power of the blocking creature and that of Shrill Howler are compared only at the moment that blockers are chosen. Changing either creature’s power later won’t cause Shrill Howler to become unblocked.