The childhood game, which is now being played by people of all ages and rather inevitably being filmed and photographed for social media posts and YouTube sees players imagine that the floor or ground is made of lava, and they must therefore avoid touching the ground.
Players stay off the floor by standing by any means possible and generally must not remain still and move around without touching the floor. There may even be a goal, to which the players must race.
Played in groups or even alone for self amusement - there have been examples of people shouting the floor is lava in busy shopping centres and strangers randomly joining in.
Anyone can start the game just by shouting "The floor is lava!" and any player remaining on the floor in the next few seconds is "out" and can not rejoin the game for some period of time but in this wave of the craze people must lay on the ground for a set period of time.
There often are tasks, items or places that can "regenerate" lost body parts or health. Depending on the players, these could be embarrassing tasks, or simple things like finding a particular person.
Of course the usual health and safety concerns apply and people must carefully consider their surroundings before playing but as with anything nowadays social media and YouTube has given rise to The Floor is Lava Extreme.
University of Leicester scientists have got in on (spoiling) the fun by using the ‘Stefan–Boltzmann law’ and taking convection into account to calculate that a high stakes version of the game with actual lava would not be possible, as the air above the lava would have a temperature too high for humans to survive for more than a few seconds.