An Ultra Wormhole is a portal that appears at gyms in Pokemon Go and allows Ultra Beasts to travel into our world from a different dimension called Ultra Space. Ultra Wormholes are unstable portals that establish a connection from the Pokemon world to Ultra Space, and they were first introduced in the Sun and Moon titles of the Pokemon game franchise. Ultra Beasts are incredibly powerful creatures that can enter the world through Ultra Wormholes. When an Ultra Wormhole appears above a gym, it means an Ultra Beast will emerge from it when the countdown ends. Players can find Ultra Wormholes by visiting the Nearby menu and looking out for the portal symbol. Ultra Beasts are just as powerful as Legendaries and could really shake up the Go Battle League meta, so when players spot an Ultra Wormhole, they will want to know exactly how they work so they can catch one.