Embiggen

The joke is a rules engine. Every characteristic Magic tracks on a permanent (supertype, card type, subtype) becomes a counting variable, so a plain Grizzly Bears gets +1/+1 for "creature" and +1/+1 for "Bear" while a legendary artifact land enchantment creature stacks the columns much higher. This is a design that treats the type line itself as a resource, which is why the payoff scales with how baroque your target creature has gotten rather than with anything the pump spell does on its own. The single exclusion clause (non-Brushwagg) exists to stop changelings, which count as every creature type at once, from receiving an absurdly enormous buff. What makes the counting genuinely rewarding is that the game is full of hidden types most players never audit; a creature that is also an artifact, or carries several extra subtypes, quietly reads as a much larger bonus than its printed body suggests. As a green trick it is deliberately unreliable, a one-mana spell whose ceiling and floor are separated by how strange your target creature is, and that variance is the point. It belongs to the small tradition of cards that turn Magic's own bookkeeping into a scoring system, asking you to know exactly how the game classifies your creatures before you cast it.