What is the highest valued pet in Adopt Me?

I'm curious to know, in the popular online game Adopt Me, what stands as the most highly valued pet among players? Is it a rare breed of cat or dog that commands a premium due to its scarcity? Or perhaps it's a fantastical creature, like a dragon or unicorn, that players strive to obtain and trade for substantial in-game wealth? It would be fascinating to learn which pet holds the distinction of being the most sought-after and expensive in the Adopt Me community.