pokemon dark energy card Basic Darkness Lot - Scarlet & Violet These cards are freshly removed from packs Cosmic Revelations - Dark Energy

This style of card was brought back in a brand new way in late 2020 in the Sword & Shield era

Although indestructible cards cant be destroyed by lethal damage or by removal spells that cause damage, they can still be exiled

It can be very brutal in combination with an Overrun effect, perhaps they left a Wildspeaker in play with 4 loyalty because they were able to kill all your creatures

Also, the decks I said it didnt belong to are a narrow band (with the main relevant one being Najeela, the Blade-Blossom)

Elesh Norn, Mother of Machines and Change the Equation make for a nice, well-rounded plan against Sunspine Lynx

Its no wonder the card is relatively expensive