My Wellspring Mask Ogerpon ex has a Sparkling Crystal attached and only one Double Turbo Energy on it. If I use its "Torrential Pump" attack, can I shuffle the Double Turbo Energy back into the deck and do damage to a benched Pokemon?
Yes, this is a case of doing as much as you can. You would get to do the bench damage even though you can't detach 3 energy, but you must shuffle in SOME energy in order to get the bonus. You shuffle the two energy that are attached back into the deck, and do 80 to the active and 100 to the bench (remember, damage is still reduced for the DTE since the detachment happens after damage is done).
Source: Stellar Crown FAQ; TPCi Rules Team (2024-09-12)
If I discard a Double Turbo Energy when using Greninja ex's "Mirage Barrier" attack, does it do 120 damage or 100 damage to two of my opponent's Pokemon?
You do 100 damage to the two. You first CHOOSE the energy you're going to discard, then do the damage (which is reduced for Double Turbo), and THEN discard the energy.
Source: TPCi Rules Team (2024-07-11)
If I have 2 Double Turbo Energy Cards attached to one of my Pokemon, would its Attack damage be reduced by 20 or 40?
It would be reduced by 40 since each card's reduction would apply.
Source: Brilliant Stars FAQ; TPCi Rules Team (2022-02-24)
Can I use Dusknoir's "Special Transfer" Ability after I attack but before my turn ends to move Special Energy cards (such as Double Turbo Energy) off of my Active Pokemon?
No, once your attack ends, your turn ends.
Source: Brilliant Stars FAQ; TPCi Rules Team (2022-02-24)