When this card is Normal Summoned: You can add 1 Field Spell Card from your Deck to your hand
All of this is to say that Oko is extremely hard to answer in combat, so it largely requires a spell to deal with it (or, as we see in Throne of Eldraine Standard, you can go way over the top of its threat generation by, for example, making lots of 2/2s with Field of the Dead)
Good luck in your Prerelease, and may Hazoret show you favor as you burn every opponent you meet
If you are a part of it, you will then compete in elimination rounds featuring best-of-three matches
Mostly, we're looking for admitted mistakes in the art, weird choices made by the artists, or instances where the art doesn't totally represent the card
OP-05 Awakening of the new Era/Protagonist of the New Era This is where things get interesting