Strangest Chemtrail Formation

Never seen a Chemtrail like this one before. That's definitely not a "Normal" cloud formation. Very strange. What exactly are Chemtrails? Some people think they are dangerous to humans, containing chemicals and heavy metals like Barium and Aluminum. What is their purpose. Some also believe that they are one of the main causes of illnesses such as dementia. Could they be part of a much bigger agenda which involves slowing down the rate of pan evaporation [blocking the sun] in order to make droughts; equating to fake / man made "climate change". Certainly something to think about.