Prison/stax decks stop your opponent from playing cards and attacking you while gaining incremental advantages over time, be it with lifegain, Treasure tokens, or card draw
It also stops the Defending Pokemon from retreating
And while a print proxy isn't legal for use in official tournaments, they can be an awesome way to playtest new deck ideas or simply have fun without breaking the bank
The Dark gave birth to the very first multicolored non-creature card Dark Heart of the Wood (which was also the first enemy-paired multicolored card) as well as the first Common multicolored cards Marsh Goblins and Scarwood Goblins , some of the scariest looking Goblins ever
Ensnaring Bridge is another powerful lock piece that effectively prevents players from attacking each other
And once you're a black-red deck with Heartless Summoning, you really can't do anything better than cast more Demons anyway