Norbert was practically a stuffed animal come to life. The three-pound mixed-breed internet-famous therapy dog dispensed joy simply by existing.

Julie Steines started posting photos of Norbert on Instagram more than a decade ago: of him volunteering at children’s hospitals, nursing homes and schools; of him dressed as a wizard or a reindeer, wearing a beanie or a tie. His tiny pink tongue hung out of his mouth much of the time.

Soon you could buy plush toys in his likeness, with profits going to charity. His mission as a therapy dog, according to his website, was simple: “to spread smiles, inspire kindness and bring comfort to those in need.”

It turns out that I, along with many of his nearly one million followers on Instagram alone, was among those in need. Any time I felt blue, I’d seek out his page for an infusion of happiness. And when I saw him pop up in my feed at random, a wave of endorphins flooded my brain.

When Norbert died last week, just shy of 16 years old, tens of thousands of comments and tributes poured in. “My family is heartbroken,” Steines wrote as part of a lengthy announcement.