I think the reptilian shapeshifter concept is mostly disinformation. Supposedly most "reptilians" do not mean us harm, but a militant group with a leader similar to "Lucifer". Nefarious entities are all around, not necessarily of the "saurian" extraction, which are generally quite noble. The forces of evil are more elemental, they indeed can shift their outwards appearance in the minds of those who perceive them, however their essential state is formless. It is an energy signature which should be avoided, which can even be exuded by cute animals, such as these woodland creatures.
http://www.youtube.com/watch?v=l1iDYZRdMpM