Rulings

• 2014-09-20
  Ferocious abilities of instants and sorceries that don't use the word "instead" will provide an additional effect if you control a creature with power 4 or greater as they resolve.
• 2014-09-20
  Some ferocious abilities that appear on instants and sorceries use the word "instead." These spells have an upgraded effect if you control a creature with power 4 or greater as they resolve. For these, you only get the upgraded effect, not both effects.
• 2014-09-20
  If there are multiple combat phases, creatures that blocked the creature targeted by Roar of Challenge in the first combat aren't required to block it again in subsequent combats.
• 2014-09-20
  If, during the declare blockers step, a creature is tapped or is affected by a spell or ability that says it can't block, then it doesn't block. If there's a cost associated with having that creature block, its controller isn't forced to pay that cost. If the player doesn't, the creature doesn't block in that case either.
• 2014-09-20
  Roar of Challenge doesn't give any creatures the ability to block the target creature. It just forces those creatures that are already able to block the creature to do so.