Couldn’t imagine how uni is alive let alone undamaged even when being squished with that much WEIGHT
Oh, but it's the softest, squishiest kind of weight. Besides, Illustrious would never let her littlest sister suffer undue stress, and I suspect Unicorn would relish any opportunity to be that close to her big sisters.
I mean... that's gotta be quite the movie, to manage to distract her from said weight.