“It’s just so shocking,” Claire Simeone, a veterinarian and monk seal expert based in Hawaii, told The Washington Post on Thursday. “It’s an animal that has another animal stuck up its nose.”

Simeone wasn’t the only person stunned by the photo of the seal and its unusual facial ornament that was shared earlier this week on Facebook by the National Oceanic and Atmospheric Administration’s Hawaiian Monk Seal Research Program. The picture — taken this year in the remote northwestern Hawaiian islands — has since gone viral, drawing attention to a rare phenomenon that continues to baffle scientists such as Charles Littnan, who is now begging the endangered seals to “make better choices.”

It all began about two years ago when Littnan, the lead scientist of the monk seal program, woke up to a strange email from researchers in the field. The subject line was short: “Eel in nose.”