The creatures were filmed off the coasts of Bali and Northern Sulawesi between 1999 and 2008 using halved coconuts humans tossed away into the ocean. The behavior was spotted four times, the BBC reported.
The octopuses turn the shells open side up, blowing jets of mud out of the bowls before walking away with them -- or if there's more than one, stacking the shells first before departing to find a place to use the coconuts as shelter, the BBC reported Monday.
"I could tell it was going to do something, but I didn't expect this -- I didn't expect it would pick up the shell and run away with it," researcher Julian Finn said.
This kind of tool use was previously thought of as only a human skill, but Tom Tregenza of the University of Exeter said octopuses are very smart.
"A tool is something an animal carries around and then uses on a particular occasion for a particular purpose. The coconut becomes useful to this octopus when it stops and turns it the other way up and climbs inside it," he said.