You can't play Battle Cards with an original energy cost of 6 or
more.
When a card in your energy is placed in your Drop Area by one of
your skills, draw 1 card, then choose up to 1 Blue/Green
multicolor card in your Drop Area, and add it to your energy in
Rest Mode; at the start of your opponent's next Main Phase, choose
up to 1 Blue/Green multicolor card in your energy and switch it to
Active Mode.