My favourites Supernatural Episode : Skin

Sam's friend, Zach, is accused of murder. Sam offers to help out by checking up on his sister, Rebecca. Rebecca claims her brother could not have committed the murder because he was with her at the time of the murder. But all the physical evidence points to Zach being at the scene of the crime. Could Zach have been at two places at the same time?

Source  http://www.tv.com/shows/supernatural/skin-488543/

I like this episode. The reason is entertaining. This episode introduce us to Shapeshifter See here for more http://www.supernaturalwiki.com/index.php?title=Shapeshifters

Written by John Shiban

Directed by Robert Duncan McNeill

Still pictures from episode

Source http://homeofthenutty.com/supernatural/screencaps/index.php

Behind the scene picture

Source 

http://www.fanpop.com/spots/supernatural/images/6471679/title/supernatural-season-1-photo