Ruling GE Houndoom's Black Fire Attack

[Hypno68]

.
Black Fire..... 40

You may discard a {R} or {D} Energy attached to Houndoom. If you discard
a {R} Energy, the Defending Pokémon is now Burned. If you discard a {D} Energy,
this attack does 40 damage plus 30 more damage.

My Question is --- do you have to discard a card? Can you
just do 40 damage and leave it at that?

 

[King Arceus]

You do not need to discard any cards to perform the attack. It says may so it isn't required. By doing that you will do jsut 40 damage and nothing else.~Mark