Another dumb headcanon of mine. Way back when bronies were trying to scientifically analyze season 1 footage, people were saying that Applejack and butterflies must be made of dark matter due to the ways they interacted with Rainbow Dash and Fluttershy respectively. I instead chose to utilize Occam’s razor and decided that perhaps pegasi are just really, really light. This would explain how they can fly despite their inferior wing-to-body ratio, as well as stand on clouds due to buoyancy. As for how there can be so little mass in so much horse… it’s magic; don’t question it.
 
For those of you with much more intelligent units of measurement: replace “15 ounces” with “425 grams”; it’s about the same thing.