Optical Illusion

What a mess of a deck list! How in the world is anyone supposed to win with this?

With luck and misdirection! Your opponent won't know what to make of half the things you're doing. You can really sell it if you act like you don't know what you're doing either!

So what's the ultimate goal? Put 12 of your opponent's Supporter cards into the Lost Zone and use Unown's "Missing" ability to win the game. (If your opponent is using a Lost Zone deck, they'll accelerate to their own demise)

A magician never

What a mess of a deck list! How in the world is anyone supposed to win with this?

With luck and misdirection! Your opponent won't know what to make of half the things you're doing. You can really sell it if you act like you don't know what you're doing either!

So what's the ultimate goal? Put 12 of your opponent's Supporter cards into the Lost Zone and use Unown's "Missing" ability to win the game. (If your opponent is using a Lost Zone deck, they'll accelerate to their own demise)

A magician never spoils their tricks, but if you decide to run this deck. Know that the best card to have in the Active spot is Mime Jr. Then you can start messing around with the background settings.

Castform and the Stadium cards are the major distractions. Use Jubilife Village to reset your bad hand. Use Chaotic Swell to block your opponent from setting up an advantage Stadium.

Castform paired with the Lysander Prism should help you clean up around 3 of the Supporter cards you need in the Lost Zone.

Barbaracle, Slowking, and the Splash Energy should create an illusion that we want to keep Slowking around. We do. But Slowking is just a compliment to the bigger picture. Let your opponent saw Slowking in half. We can put him back together later. With Barbaracle in play, there's a chance we added another Supporter card into the Lost Zone. 

By using Hiker and Chip Chip Ice Axe, with Trumbeak, we can increase our odds of pecking out more Supporter cards.

The best way to pull off the illusion is to try to keep Unown off your bench for as long as possible. Once your opponent understands the ability, they are going to try to get rid of it ASAP. 

This is a stall deck with a bunch of wasted space with the Castform, Stadium, and Lysander set up involved. Your opponent is going to be mad as get out when Mime Jr. Takes the stage. Best case scenario. You'll win in 9 turns. Should be less than 15 turns. If both Unowns are trapped in the Prize Cards. You have to cross your fingers that they mill out, because you'll never win otherwise. 

Good luck. Expect small children to be amazed and infuriated by your antics. Probably get the same reaction out of a gullible adult. Fun for the entire family!