Magic: The Gathering Unfinity card is made Eternal-legal through clever use of language

sportskeeda.com:

Magic: The Gathering’s “Unfinity” expansion has some truly ridiculous cards, but one of them, Embiggen, could have been starkly different. Had it gone through without a straightforward wording, Changeling decks could gain a creature with enormous buffs to their attack and defense for one green mana.

So what was changed to make this impossible? The spell only targets “Non-Brushwagg” creatures. Why does this work, and what makes this such a great card?

There are so many cards in Unfinity that could make Magic: The Gathering decks truly terrifying. In particular, Embiggen skirts that line between “moderately balanced” and “was almost horrifyingly overpowered.”

But what exactly does this spell do? For one green mana, it casts at Instant speed and triggers the following effect until the end of the turn.

Card Type refers to the actual type of the card - artifact, land, creature, enchantment, et cetera. Supertype is something that precedes the card type. So a Legendary, Basic, Snow, these are all supertypes. Then there’s the subtype. Subtypes follow the card type. So, things like Soldier, Skeleton, Frog, Atogg, Lhurgoyf, et cetera.

This can potentially be a serious buff to one creature for one mana, but not something outrageous. Land creatures, for example, can easily gain +3/+3 or +4/+4, thanks to being a Land, a creature, and things of that nature.

The reason it’s Eternal legal in Magic: The Gathering is because of “Non-Brushwagg.” This directly targets Changelings. Changelings are all creature types at the same time. Choosing a Changeling will not work because they are also a “Brushwagg” creature.

Otherwise, that creature would easily gain 300 or so +1/+1 counters for one mana at instant speed.

However, it’s worth noting that there