Cyclizar is a Dragon/Normal type Pokémon that is new to Pokémon Scarlet and Pokémon Violet. It brings a new move, Shed Tail, that creatures a substitute before swapping places with a Pokémon in your party.
The official Pokémon website also details the Battle Stadium feature for Scarlet and Violet. There are two different forms of battling: casual and ranked. Casual battles are what they sound like: low-stakes Pokémon battles where you can use any Pokémon of your choosing.
Ranked battles are more high-stakes affairs, complete with an ELO-style rating. Pokémon Scarlet and Pokémon Violet will feature support for online competitions in both an official and friendly manner. The ability to rent a Battle Team will be available as well.
As a disclaimer, you’ll need to be a paid Nintendo Switch Online member to participate in online play. Nintendo also notes that Pokémon Sword and Pokémon Shield players cannot battle against Scarlet and Violet players.