Some Pauper decks use it as a wincon alongside Ghostly Flicker and Archaeomancer to soft-lock their opponent from combat
Plenty of ways in the deck to recover counters too, so this should give you a solid ramp to get into midgame if you draw it early, but even late it will fuel your big haymakers and let you thin your deck
It had already been decided that a trading card game was on the cards (pun intended), but before any official release, prototypes were made in order to test game mechanics and playability
If a player has 10 or more poison counters, they instantly lose the game
It makes cards like Aetherflux Reservoir incredibly easy to activate multiple times, and quite literally doubles the value of any lifegain source you have
In particular, it will stand out in the Mad Party meta, which is dependent on having several Pokmon cards with that attack in your discard pile