Delvernois shared a photo of his group toasting their success with mini-whiskey bottles. But the photo quickly went viral as viewers realised that there appeared to be only three arms in the photo - but four bottles of whiskey.
The photo was shared on Reddit and subsequently to Twitter by user Jen Gentleman, who captioned it "my brain refuses to believe there are four people in this photo".
The post racked up over 200,000 likes and 40,000 shares from fellow internet users similarly baffled at the shot.
On closer inspection, it becomes clear there are actually four arms in the photo - but one of Delvernois' friends is wearing such an effective camouflage jacket he blends seamlessly into the surroundings.