Wish Park is a world in PokéPark 2: Wonders Beyond alternate to the PokéPark. You first encounter it when you meet Sandile and Krokorok in the Cove Area. It is set within an endless void, and the Pokémon there seem to be controlled.
When you reach Wish Park, Pikachu and Piplup head for Cofagrigus' Attraction. After they win, they are about to eat a cake when Pansear stops them. Before he can explain, though, Cofagrigus interrupts and shoves a cake in his face, which seems to make him like the other Pokemon there. He tries to give Pikachu and Piplup cakes, too, but Oshawott uses Razor Shell and destroys the cakes. In turn, Cofagrigus angers and challenges Pikachu, Piplup, and Oshawott to a battle. They beat him, and Gothita shows up to take him away. Gothita then lets them ring the Wish Bell there, and they do, which releases the Pokemon from Wish Park's control. However, Darkrai shows up and captures Piplup, but fails to get Pikachu and Oshawott.
When you confront Sandile and Krokorok, you battle them to interrogate them about how to get back to Wish Park. You are told that it takes a great deal of friendship power to open the portal. After finding ways to befriend as many Pokémon as possible, you summon all the power you can muster to reopen the portal to the Cake Zone. This time, you must play the Cake Contraption a second time. When you clear the attraction, Cofagrigus challenges Pikachu and Oshawott to battle again. They destroy the cake that Cofagrigus is on, and then best him in battle. This clears the path to the Wish Bell, which frees all the Pokémon when rung. But Cofagrigus tells you that this is only one of four zones that make up Wish Park.