I wonder how I could make an invisible-effect like in this video at http://www.youtube.com/watch?v=EbD6YPbrw8Q&feature=related#t=0m45s (you just have to watch 5-7 seconds ;D) The guys in the video are invisible, but on the other hand you can recognise their forms. How can I make such an effect to a gameobject?
I bet this would get you close: http://forum.unity3d.com/threads/50132-Heat-Distortion
You'd want to factor in the dot product of the surface normal and the camera forward vector do decide how much to distort.
Add a white texture. If the photo format is .gif it will be clear. White in .gif = transparent.
There's a Diamond (or Gem?) shader out there, I've seen this type of effect using it.