Without the slightest premonition of any issues with his health, Pyotr Verzilov, a Russian opposition activist, suddenly fell violently ill two years ago and slipped into a coma, a common problem for opponents of the Kremlin.

Verzilov, who is known for staging anti-government performance art, displayed the same, mysterious symptoms that struck Alexei Navalny, Russia’s most prominent opposition politician, on Thursday as he was on a flight to Moscow.

"I was in exactly the same condition,” Verzilov said in an interview Thursday with Rain TV, an independent Russian television station, of his monthlong illness in 2018.