>>36153108I think the biggest problem is that there's no counterplay and no chance of failure at any point during the game- you just have to have it in your hand when your opponent hits 3 or 4 prizes, and considering how fast games go and how much drawing power there is, that reeeeeally isn't hard at all. You're basically guaranteed free acceleration in na UB deck. Now, granted, one could make this same argument for Aqua Patch, but that still requires setup, and you're limited to one on the bench. Beast Ring requires no setup, you get two from your DECK, and they can attach to your active too.
The only reasonable nerf would be to make a way to play around it- changing the prize requirements, requiring creativity avoid activating it (e.g. 5, 3 and 1 prizes), making it whiffable (look at the top 8 cards for energy), or making it a much more blatant nerf (1 energy to 1 of your benched Pokemon).