Forum:Ancient gear golem...again

The effect of Ancient gear golem is "During battle between this attacking card and a Defense Position monster whose DEF is lower than the ATK of this card, inflict the difference as Battle Damage to your opponent." Thus, between Battle Damage or Effect Damage, which one it should be? And can I use Phantom of Chaos (has Ancient Gear Golem effect) to inflict damage to opponent when it attack a defense monster.