‘I can’t explain what we saw, and I went down there to answer questions, but I came up with even more questions,” said Stefan Hogeborn in a statement.
Hogeborn is one of the divers from Ocean X Team, which examined the object on the Baltic sea bed earlier this month.
The strange object, often likened to the Millennium Falcon from Star Wars due to its unusual shape, was discovered in June 2011 by divers using sonar equipment in search of interesting shipwrecks.
What they discovered instead was a large, round formation, and a mystery to boot.
No one has yet been able to explain how the object got there, and several international news stations, including CNN, reported on the bizarre find.
Because of lack of funding, the object has remained unexamined until the present day.
The Swedish expedition Ocean X Team made the 85-metre dive in hopes of debunking the many theories that surround the mysterious formation.
What they discovered only provides further mystery: 60 metres across, the object has rounded sides and rugged edges.
A trail over 300 metres long leads up to the object, and divers have described the stretch as a “runway” of some sort, which may indicate that the object skidded before stopping.
The mystery object is raised several metres above the seabed, with sides that curve in, in the shape of a mushroom.
“First we thought this was only stone, but this is something else,” said diver Peter Lundberg in a statement.
At the object’s centre was an egg-shaped hole, surrounded by strange rock formations they describe as similar to “small fireplaces” covered in something bearing likeness to soot.
“Since no volcanic activity has ever been reported in the Baltic Sea the find becomes even stranger,” said Lindberg.
Swedish newspaper Expressen showed footage from the dive to Martin Jakobsson, professor of marine geology and geophysics at Stockholm University.
“It’s probably some sort of sandstone, from what I can tell from seeing the structure,” he said.
Samples from the find have now been sent for analysis.
Meanwhile, the Ocean X Team is hopeful that their mysterious discovery will interest tourists, UFO hunters or shipwreck divers willing to pay for a submarine trip to see the site for themselves.