Expansion

A keyword that allows a balloon to come into play on top of another balloon of a specific class by paying the difference in size between the balloons in breath. if the host is bigger than the expansion then it technically free, but if the host is bigger because of breath tokens then you still got to pay the difference in breath tokens. it's more intuitive than it sounds.

Expansion is a key mechanic of this game as a whole, a sort of "evolution" mechanic where you turn a smaller balloon into a larger balloon. it also allows you to get bigger balloons in play sooner by reducing the cost with a balloon on your field.

Now the key downside to this is that it costs you 2 cards. which is a bit of a nerdy thing to care about but hand advantage is still something to consider. but one big upside with expansions is that balloons don't come into play stiff, and are able to attack right away.

so in many cases, you're paying 2 cards to get in a big balloon that can act immediately. and that's often worth the price when you're trying to close out games.

So far within the prototype decks, most of their size 4+ balloons have Expansion. this is in part due to a recent change where before Expansion was only on a separate class of balloon. that class no longer exists so now we just have big balloons with the expansion keyword. This does beg the question of when should a large balloon not have expansion. and it's a good question. only answers I have so far is if the balloon has other ways to cheat itself in, or if the effect is just that potent that I really don't want it that early.

it's a case by case thing.