Lost gray chinchilla with blue harness

I lost my gray chinchilla, Niko, yesterday around 3pm. He's the size of a small loaf and fluffier than a cloud, with soft gray fur and a lighter belly, plus a tiny tan patch behind his left shoulder. He wears a blue micro-harness with a small silver bell that jingles when he runs. Last seen near the Golden Dome on the Notre Dame campus in South Bend, at the Michigan Street entrance, but he could have wandered toward Eddy Street or the riverfront behind Studebaker National Museum. This little guy means a lot to me—rescued from a shelter and it would mean everything to have him back safe. If anyone spots him, please message me ASAP; I really need him back.