So, take a quick glance at this picture and tell me what do you think is going on; here’s a hint: it involves cicadas, and cicadas do this all the time. Weird bunch, huh ?
The thing is that there are actually not two cicadas in this picture, there’s only one, and it’s shedding its exoskeleton, which is just what they do after a while, usually to let their organism grow; this process is called ecdysis, and it takes place because the exoskeleton is rigid and cannot allow growth, like skin does, for example. It’s pretty much what snakes do too, when they shed their skins.