What it's actually meant to represent
The halo is about watching over, not about loss. It's meant to represent the quiet, constant attention a pet with an ongoing condition needs, someone keeping an eye on things even when nothing looks wrong that day. That's the whole function of the app in one small mark.
Why not just a paw
A paw print alone says "pet app," which is accurate but says nothing about what kind. Halo isn't a generic pet organiser, it's specifically built around the more attentive, more careful end of pet care, chronic conditions, multiple medications, regular vet involvement. The halo is what signals that difference at a glance.
Where it shows up
The same mark appears everywhere across the app and this site, from the app icon to the outro of every social video, deliberately kept identical everywhere rather than redesigned per platform. Consistency was the point, not novelty.
It's a small detail in a much larger design decision, the same one behind why Halo is cream and rose instead of clinical blue: nothing about the visual identity was left to default.