2014-07-18
As soon as Inferno Fist leaves the battlefield, its power bonus stops applying. This means that if you sacrifice Inferno Fist before combat damage is dealt, perhaps to destroy a potential blocker, the creature that was enchanted won't have the bonus when it deals combat damage.
2014-07-18
If another player gains control of the enchanted creature, or if Inferno Fist becomes attached to a creature another player controls, Inferno Fist will be put into its owner's graveyard as a state-based action.