New Zealand’s reputation as a place for unusual creatures not often found anywhere else in the world is well deserved, but back in 2004, a keen fossil hunter stumbled across the bones of something that baffled even scientists. Now, they have revealed they belong to a newly described species of giant penguin, one that would have stood as tall as a man.

World, meet Kumimanu biceae, a literal monster (Kumimanu means “monster bird” in M?ori) that would have measured around 1.77 meters (5 feet 10 inches) at maximum swimming length and weighed around 100 kilograms (220 pounds).

This was no tap-dancing, tuxedo-wearing little cutie.

Described in the journal Nature Communications, K. biceae has been dated to the late Paleocene 60-55 million years ago, and although not the largest giant penguin fossil ever discovered (that would be the 2-meter-tall Palaeeudyptes klekowskii discovered in 2014), it is the oldest.

Discovered by The Museum of New Zealand Te Papa Tongarewa’s curator Alan Tennyson and colleagues on Otago beach near Christchurch on the South Island in 2004, the bone fragments sat on a shelf at Te Papa until 2015.  

“When we found it we didn’t know what it was, because it was completely encased in rock,” Tennyson explained. “But as soon as the extraction began, we realised that is was the remains of an enormous bird.”

Along with co-authors of the study, Paul Scofield and Vanesa De Pietri of Canterbury Museum, and Gerald Mayr of the Senckenberg Research Institute and Natural History Museum in Frankfurt, Tennyson identified the fragments of leg bone and flipper as a previously unknown species of colossal penguin.

And it was not a penguin to be messed with.

“It’s difficult to determine exactly what it would have looked like in life, but it would have been very impressive, as tall as many people, and a very solid, muscly animal built to withstand frequent deep dives to catch its prey,” Tennyson said.

“It would not have been the kind of bird that someone could catch alive, it would have been considerably more powerful than a person.” 

The authors suggest in their study that the date of this new fossil lends evidence to the idea that gigantism in penguins evolved shortly after they became flightless divers. 

However, evidence also suggests these ancient giant penguins went extinct around 20 million years ago, coinciding with the rise of toothed marine mammals such as whales and seals, though it is unknown whether this was due to competition for prey or being prey themselves.