A Chocobo Booster is a special kind of booster pack thats unique to the Chocobo Bundle
It's likely that as soon as this comes down for five mana, you're giving a creature +7/+7, between your Delirium -rich graveyard and the rest of the table
There's a lot more to share about rotation, and you'll see additional information both in game and later in July as we share more about what's coming next for MTG Arena
You could compare this to drawing a black line on the back of a powerful card or one you know you need for your planned strategy
In the foreground, that's clearly Gimli, Legolas, and the rest of the heroes, while in the background the riders of Rohan and Oliphaunt cavalry each get their own card
That way, every card acts as an invitation to learn more about the game it references