Savage Punch

• WOTC Official Reminder Textofficial rules
  Fight — Each of those creatures deals damage equal to its power to the other.

• WWizards of the Coast2014-09-20
  Official Ruling
  If either target is an illegal target when Savage Punch tries to resolve, neither creature will deal or be dealt damage.
• WWizards of the Coast2014-09-20
  Official Ruling
  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.
• WWizards of the Coast2014-09-20
  Official Ruling
  Assuming the ferocious ability applies, if just the creature you control is an illegal target when Savage Punch tries to resolve, it won’t get +2/+2 until end of turn. If the creature you control is a legal target but the creature you don’t control isn’t, the creature you control will get +2/+2 until end of turn.
• WWizards of the Coast2014-09-20
  Official Ruling
  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.
• WWizards of the Coast2014-09-20
  Official Ruling
  You can’t cast Savage Punch unless you target both a creature you control and a creature you don’t control.

Rulings via Scryfall