RATE PLEASE, IF YOU LIKE IT.
The drawings came from grand-illusions.com, I have no idea where that guy got them from.
And here is a stopmotion I made for fun. The camera captures the illusion effect at the end.
Step 1: Download and Print the PDF
Step 2: Cut out the dragon.
Step 3: Fold your dragon
Mind that I think there is an error on the head of the dragon where instead of a valley fold, it is actually a mountain. Make sure that along with checking the fold orientation, also check it with the image below.
When you are done folding, tape on the tabs around the mouth and base of the dragon.