They cannot attach Energy (which is provided from the Energy Zone instead of being part of the deck), attack, or evolve a Pokemon that turn
The only sealed source is the 151 Ultra Premium Collection, where it comes packed in the box as one of the included promos
That's when someone came up with the idea of the creature stealing Goats
This can both prevent them from bringing out their best tactics and potentially cause them to run out of cards to draw, which would result in them losing the battle
Cultist of the Absolute Cultist of the Absolute seems better than it is, but this black enchantment is good value for its cost even if you're not using it as a background
14 Yorion, Sky Nomad Do It All Again An incredibly versatile commander, Yorion cares about one thing only: enter the battlefield triggers