A video making the rounds online shows a group of people pulling the pin on a hand grenade, throwing it into the water, and filming the moment it explodes. Their reason, as described, was simple curiosity, since they wanted to see what a grenade blast actually looks like underwater. The footage captures the detonation and the water's violent reaction, and it is exactly the kind of clip that makes viewers wonder how anyone thought this was a good idea. Details about who the people are and where the video was filmed were not provided, so those questions remain open.

Experts say the stunt is far riskier than it looks. Science explainers note that an underwater blast is usually more dangerous to anyone nearby than the same explosion on land, because water carries the shockwave with very little loss and can cause severe internal injuries, especially in air-filled parts of the body. Grenade fragments slow down quickly in water, but on land they can fly hundreds of meters, which is why trained soldiers throw and take cover immediately. Past viral clips have also shown grenades going off at the wrong moment, including one from 2012 where a grenade exploded the instant it hit the water and knocked its throwers off their feet. A grenade with the pin pulled cannot be made safe again, so the most important takeaway is not to copy this under any circumstances.