pokemon base set booster box 1999 Pokémon Pack - Unlimited Edition (1999) The pack is light and features select artwork Sealed 1999 Base Set Booster

It was just like having free power, but that power is not quite so free any more

(Scryfall note, 2020-06-01) Wizards of the Coast has issued functional errata for the Companion mechanic

There's a lot of stuff going on with Vraska, Betrayal's String that makes it worth the steeper price point, such as the aforementioned Poison Counters, the Proliferate effect, and even the ability to neutralize threats by turning them into treasure artifacts with its most costly attack, this card can end the game with its Poison Counters alone

As the only Ooze lord, as far as I know, it will also definitely fit into any Ooze-themed The MimeoplasmThe Mimeoplasm decks