The Koala Challenge is trending online and it looks pretty difficult. Whether you are the "tree" person or the "koala" person you need to be very physically fit to participate in this Koala Challenge.
Basically one person stands there like a tree while the other person crawls around them like a koala does around a tree.I wouldn't recommend trying it unless both of you spend a lot of time in the gym. Oh and the "koala" person needs to be quite petite to pull it off, while the "tree" person should be pretty tall so that the "koala" person can fit through their legs. This sounds crazy trying to describe what they're doing in this viral challenge so why don't you just watch it to see for yourself how it works.