I am not sure if he is not just deceived. When people are heavily demonized, they are open to influences and illusions from Satan. It is possible that he saw someone shape-shifting.
If I remember correctly he said he has never seen someone shapeshift. The one thing I do know is that people like Icke turn the nwo agenda into something crazy with all his tales of lizards etc. The nwo is real but when you have someone saying they are a bunch of lizards trying to rule the world they immediately dismiss the whole nwo truth.