Supplies
Plastic eggs
Primer
Paint in different colours and shades Moonmuck (a.k.a. slime)
Small toy dragons (Yu-Gi-Oh dragons or others like this)
Small cauldron
Polyfill
Preparation (Before the Party)
Prime the eggs and paint them. You can look through the books (or the Harry Potter Lexicon Dragon Page) or create your own variations, for example by painting the eggs in various shades of gray and black and adding speckles and dots.
Add a dragon and a small amount of slime inside the egg.
Place the eggs in a small cauldron filled with polyfil.
Animation
Explain the kids what is in the cauldron, and that you have received special permission from the Ministry of Magic for your students to raise dragon eggs (very important, as it's against wizarding law to own a dragon).
Carry on explaining that dragon eggs need to be kept warm and place the cauldron near the fireplace.
Before the kids go home, have them reach into the cauldron with their eyes closed and choose an egg. Then watch their faces as the eggs “hatch”.
Final Product
Credit
© Jennifer Ofenstein (ofenjen)'s activity was taken with permission from Sewhooked.org
