What is your question? The Mac didn't automatically format and start backups. When a new drive is connected your mac will ask if you want to use it for Time Machine, you must have clicked yes and then it formatted the drive and started the backup.
1. So now why I see 3 Drives ( First Pic ) ?
It should be one ...
There are 2 drives showing, not 3, and the 2 that are showing are the same drive (unless you have 2 x 1.5T Samsung Drives)