(CNN) Scientists who visited one of the world's newest and most unique islands last year discovered a mysterious, sticky mud, said NASA.

The island is located in the South Pacific near Tonga and is unofficially called Hunga Tonga-Hunga Ha'apai (Hunga Tonga). It came into being after a volcanic eruption in late December 2014 connected two older islands. NASA says it is the first island of its kind formed since satellites began consistently taking pictures of Earth.

Scientists initially predicted it would be around for just a few months. But a NASA study released in 2017 found that the island survived "against all odds" and could last from six to 30 years.

Scientists have been mapping Hunga Tonga closely since its formation using aerial and satellite surveys, but it wasn't until a team traveled to the island by boat in October last year that researchers became aware of its unique vegetation.

"We were all like giddy school children," said Dan Slayback of NASA's Goddard Space Flight Center in a post on NASA's Earth Expedition blog on January 30 detailing the research trip.

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