Homo Insanus

A human subspecies that is generally regarded as "crazy" by the rest of the human population. They are visually indistinguishable from homo sapiens. The only why to distinguish the two is through their behavior or a brain scan. They can be found in large numbers in the US, Australia, Ireland, and former Soviet Union countries. Do not be alarmed by them, just remain at least ten feet away when they give into their natural instinct to cause chaos.

"It's bird!"
"It's a plane!"
"No, it's Homo Insanus."