We've all seen the Adrian designs and the #rocky mate bad as hell statement, both of which I adore. I love that we as a fandom have agreed that Adrian is an absolute catch, but, and stay with me for this, what if they weren't?
We've decided that Adrian is a big, pretty blue/green rock who Rocky is obsessed with, and Grace is intimidated by, but in the same way that we sometimes find hot people intimidating. The complex color, the way light reflects off of the geode structure, and the patterns you can see underneath. Absolutely beautiful, but would Eridians have the same society beauty conventions? They don't perceive color or light, and those inner patterns, depending on the geode, are often viewed as imperfections by collectors. Would Eridians also see those inner imperfections and view them as not attractive?
Much like we are supposed to look at Ryan freaking Gosling as Grace and interpret him as somewhat of a loser within the world of the movie, within the Eridian society, Adrian is considered a catch for many reasons, their size for one, but being attractive is not one of them. The uneven mineral deposits and the way their surfaces are angled affect the way sound bounces of them. It's not necessarily unpleasant, just not overly desirable. Adrian is just as typical as any other Eridian, but they are compared to impossible beauty standards that so few actually meet.
Of course, Rocky thinks Adrian is hot as hell, but he is in the minority, claims everyone else is stupid, so when Rocky brings home this leaky space blob, who seems transfixed by Adrian, Adrian thinks Grace is just being polite towards them for Rocky's sake, but the more time they spend around him, the more genuine they realize he is.
This alien can perceive things that none of their species can, and the blob says everything about them from their color, to the light reflections, to how their inner patterns seem to dance when they move, none of which Adrian can actually comprehend, makes them stunning to look at. Mesmerizing even. Yes, Rocky thinks Adrian is beautiful, but Adrian acknowledges a certain amount of bias there, but this foreign being, whose standards of what is attractive are just as incomprehensible as he is, says they are beautiful in ways that no one but he will ever be able to perceive. Adrian can't help but do whatever the Eridian equivalent of blushing is.