Taking the expression quite literally...
A French performance artist has just completed a week's stint living inside a boulder.
Abraham Poincheval spent a week living inside a rock, sucking oxygen through tiny air holes and storing days' worth of his own waste in bottles closely around himself.
"I'm a little dazed, which I imagine is totally normal after one week living in a rock," he told reporters who had gathered at Paris' Palais de Tokyo museum to see him emerge from the more than 10-ton boulder.
He then thanked the rock, "for having been so enthusiastic about welcoming me."
"It's this strange feeling of a floating world, an incredible floating in this mineral capsule," Poincheval said. "There are very strong moments of getting dizzy, where the world is shaking monstrously.
"It's a moment of happiness, it's a gift," he added, "but at the same time one must stay clear-headed. There are very strong moments where you lose yourself, where suddenly you don't know anymore where you are."
Previously, he lived under a rock, in a hole in the ground beneath a bookshop in 2012, which he called 604,800 Seconds.
In 2014, he spent nearly two weeks living inside a bear carcass at the Parisian Hunting and Wildlife Museum, repeating a feat he'd performed the year before. While inside the bear, he subsisted on worms and beetles.
"For him this act signifies a rebirth, a rite of passage, to pass from the world of the dead to that of the living," read a 2014 press release.
For his next project, Poincheval will be returning later this month to the Palais de Tokyo, where he will begin a work he simply calls Oeuf (or Egg, in English).
Beginning March 29, he will be sitting atop a dozen hen's eggs for approximately three to four weeks until they (hopefully) hatch, only taking one half-hour break each day.
Those chicks that hatch, he told The Guardian, "will go and live with my parents."