Umbreon VMAX from Evolving Skies, Gengar VMAX from Fusion Strike, Pikachu ex from Surging Sparks - they're all expensive cards, at mind-boggingly high prices for most Pokmon TCG collectors
Food is an artifact type
Scarcity creates value, and if many people are going after a particular card, it eventually becomes low in supply, increasing its value over time
Its trainer, or caretaker, appears to be fitting a riding harness on its back in preparation to ride it
Prices vary widely, near-mint copies can command hundreds, sometimes over $300, depending on edition and condition
We then represented this in a form thats tractable using machine-learning and we just trained a recurrent neural network to predict the next price move (given the last price move and an attribute indicating whether or not the card was reprinted)