I’m sure these have been done before, but it was just something I thought up while making the other eggs. Place egg into an egg cup (or other holder that will hold to egg upright). I placed mine on a plate to catch the drips. Use the spray bottle to mist the top of the egg.
Squeeze a drop of food coloring onto the top of the egg.
Hold water bottle at a distance and mist the top again.
Add additional colors.
Mist or blow on the egg to create the desired effect.