Flygon's first move is called Reactive Blast and only takes 2 energy cards, 1 colorless, 1 electric and does 40+ damage depending on if you want to discard any react energy cards from Flygon while you perform the move, so in essence, Reactive Blast can do 100 damage for 2 energy cards, if both your energy cards attached to Flygon are react energy cards
It can be challenging to play a card like Chalice of the Void on 1 without also hindering your own play, but its not unheard of
Not only does this creature buff all your other dragons with a global +1/+1, but thanks to its storm ability, you can end up with a sudden army of flying beaters if you chain a few spells together
In total, this card requires five colorless energies to use its special attack, which isn't bad at all
It is the highest graded example that exists