Pokémon Sword and Shield has a new evolution for Zigzaton, giving the second generation of Pokémon a third form called Ixon. He stands on his hind legs and has his arms crossed in front of his body. It wants to fight and it's a Black and Normal type Pokémon.
There are two methods to acquire Ixon in the game. The first and easiest method is to catch a Zigzaton or Lineon. You can see them all on the map, especially in the Wild Area. If you get a Zigzaton, you need to work your way up to level 20 to turn it into Lineon.
After you get Lineon, you need to level it up to 35. At level 35, you need to level Lineon up when it's dark. It only works at night, so if you're trying to get an Ixon, make sure it's at night, otherwise it won't work.
The other alternative to acquiring an Obstagon is to find them in Lake Outrage in the Wild Area. You won't be able to reach this location until you can cross water with your Rotom bike, which will happen when you reach Route 9. You get this upgrade from a scientist who is harassed by a pair of teams. Scream The grunts. Handle the grunts, and the scientist will thank you for upgrading your bike.
You'll probably be lucky enough to get your Lineon up to 35 long before you reach Route 9; it is therefore very quick to make it evolve at night.