Unicode SKULL AND CROSSBONES – The Still Life (Photo credit: schoschie)
Windows also hides file extensions by default, which is another way novice users can be deceived – a file with a name like picture.jpg.exe will appear as a harmless JPEG image file.
Read More http://www.howtogeek.com/127154/how-hackers-can-disguise-malicious-programs-with-fake-file-extensions/