Colorado - After buying a cow on Facebook, a mystified young couple suddenly found a calf in their pasture in a surprise two-for-one offer.

Meredith Weber and her husband Travis had fallen in love with the 3-year-old Highland heifer named Fiona via a Facebook marketplace listing.

According to the ad, Fiona had been raised as a pet and lived alone with a goat.

Note: There was no mention of her living with a bull, let alone being pregnant.

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But during a routine check on her farm in Colorado, Meredith suddenly discovered that Fiona had separated herself from the rest of the herd.

When she got closer, she couldn't believe her eyes – a newborn calf was jumping around next to Fiona!

At first, the woman had thought it was a dog, but then all became clear.

"POV: you bought a cow on fb marketplace who had never been exposed to other cows and two weeks later you walk out to this," reads a now-viral video's humorous onscreen text.

But how had Fiona gotten pregnant in the first place? Well, her new owner soon got to the bottom of that mystery!

Because no one knew how Fiona had become pregnant, Meredith called the previous owner – but he was also completely surprised.

Only a neighbor of the previous owner was able to shed light on the situation.

Apparently, Fiona had escaped nine months earlier after a storm and had strayed onto the neighbor's property.

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There, the cow had come into contact with a miniature bull. The result: the calf, Fern.

The little family had a happy ending, as Fern was adopted together with another calf and now lives on a farm with a petting zoo and pumpkin patch.

Fiona herself is doing well – and, according to Weber, is already pregnant again!

The internet reacted enthusiastically, with many joking that the unusual birth was an "immaculate conception."