Balefire Dragon has an ability that triggers when it deals combat damage to a player. When the ability resolves, the Balefire Dragon itself will deal damage equal to the amount of damage it dealt to the defending player to each creature that player controls. In most cases, this is pretty simple; but as always, this can change depending on interactions with other cards and abilities.

This ability will not trigger if the Dragon does not deal any combat damage. If Moonmist is played, the Dragon will not deal any combat damage this turn, so the ability will not trigger.

If the Dragon is given Trample and blocked by a creature, this ability will deal damage equal to the amount of damage that has ‘trampled’ over. For example, if the Dragon is given +4/+0 and Trample by Kessig Wolf Run, but it’s blocked by a Chancellor of the Dross, the Dragon can do up to four points of damage to the defending player. When its triggered ability resolves, four points of damage will be dealt to each creature the defending player controls.

Finally, if some of the damage is prevented but not all, then the ability will deal less than six points of damage. If the ability of Abuna Acolyte is used to prevent one point of combat damage from the Dragon, then the Dragon’s ability will only deal five points of damage.