French artist Abraham Poincheval has entombed himself in a 12-tonne rock, planning to stay inside for a week. He’s currently inside the boulder, with a space in the middle cut in the shape of his body, at Palais de Tokyo modern art museum in Paris, and is speaking to people through a small crack.

The 44-year-old artist has a supply of water, soup and dried meat, and has to store his own excrement beside him. He is keeping a diary while inside, which he plans to publish after the performance. As the Guardian reports, Poincheval described the experience like “tripping”.

“I am travelling in this rock without moving, like an astronaut,” he said. “People seem to be very touched. They come and talk into the crack, read poetry to me, or tell me about their nightmares or their dreams. They are not so much talking to me, I think, as to the stone. I am very happy that the stone has got into their heads.”

Poincheval previously completed two weeks inside a stuffed bear, eating worms and beetles to survive. He was also buried for eight days, spent a week on top of a 65-foot pole in Paris and went down the Rhone river in France in a giant plastic bottle. If he gets through this prolonged performance, he wants to hatch a dozen chicken eggs by sitting on them.

The artist related that the strange sleeping patterns are what affects him most, as he can’t tell what time of day or night it is.

“I do not feel oppressed (by the rock), I feel completely at ease, in real connection with it,” he said. “Right now, it’s sweet. Like when you are starting to climb a mountain. But I know it will get difficult.”

He told AFP: “We are already locked into our own bodies,” and referred to the boulder as a “beating heart”.

“It’s very complex. You pass from one feeling to an another. Like you are being carried away on a raft,” he said of the experience so far. “It’s like tripping. I am trying to explain (the feelings) in language but it very difficult to put down in black and white.”