Nuova Shenron, the Pyromancer (BT12-110) - Vicious Rejuvenation

[Auto] When this card is played, choose up to 1 of your opponent's Battle Cards with an energy cost of 4 or less and switch it to Rest Mode.
[Auto] If your Leader Card is a "Shadow Dragon" card : When this card KOs an opponent's Battle Card by attacking it, choose up to 1 "Nuova Shenron" card with an energy cost of 4 from your deck or hand and play it on top of this card in Active Mode, then shuffle your deck if you looked through it.