If you have less Benched Pokémon than your opponent, each of Houndoom's attacks does 40 more damage to the Active Pokémon (before applying Weakness and Resistance).
Attack 1:
[1] Burning Sensation (20)
If the Defending Pokémon already has any damage counters on it, the Defending Pokémon is now Burned.
Attack 2:
[RR] Bright Flame (60)
Flip a coin. If tails, discard 2 Fire Energy attached to Houndoom.