The permanent card can be one you milled while manifesting dread, but it doesn't have to be
#6 GX Ultra Shiny (28.0/40) The original shiny card set
What sets it apart is that unlike other cards that turn just one artifact into a creature, this one turns all treasures you control into 3/3 construct assassins until the end of turn
This wants to cheat out creatures, especially its werewolf packmates
Stick to platforms like TCG CARDIFY, eBay (with buyer protection), and the Pokmon official site, where sellers are held accountable and you can verify the authenticity of your purchase
Colloquially known as Alpha, this set has some incredibly powerful cards, combined with the fact that it had a limited printing, and is more than 30 years old, makes just about every card from this set cost a pretty penny