When Dion enters, create a 2/2 white Knight creature token
Get him in a deck with Jinnie Fay, Jetmir's Second (So maybe a Jetmir deck, just to be easy), and you suddenly have a very easy way to create Cat tokens through Jinnie's replacement effect, and a few wincons: Jetmir just steamrolls things with huge numbers, or Ajani blows your opponent off the board with the 0 ability once he's flipped and your bazillion tokens hit like a truck
Personally, I'm most excited to see the throwback mechanics of Storm and Suspend on the mythic rares
Theres even a micro-art cycle of crabs on rocks looking dramatic and thoughtful: Hedron Crab and Thassa's Emissary
This card is also an example of one other thing done in the design
Built from multiple materials, she hits the field with high ATK and, more importantly, several monster negates ready to go