Hunters are baffled after finding a mountain lion in Idaho with a second set of teeth and small whiskers growing out of the left side of its forehead.

The cougar reportedly attacked a dog near the Idaho-Utah border. A hunting party legally tracked and killed the mountain lion on Dec. 30, and Idaho Fish and Game released a picture a few days later. The dog was severely injured but survived.

"They tracked it down for a while in the afternoon, and they brought it down to let us know they'd gotten it. ... I did see that weird feature on its head and handled it, and it was pretty strange," the owner of the dog that was attacked told KSTU.

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Idaho Fish and Game officials said they "cannot definitively explain why this abnormality developed" but speculate the teeth could have been from a conjoined twin that died in the womb, or it could be a teratoma tumor — a rare condition in which teeth, hair or even fingers emerge.