We've all seen this one: Our ninja is outnumbered and throws an egg to the ground which bursts into a bright fiery flash and thick cloud of smoke concealing his getaway.

Step 1: Initiator (what Gets It Going).

I had tried a number of so called contact explosives; nitrogen triiodide, fulminated mercury, nitroglycerin. None of them were suitable for a number of reasons. Finally I came up with this design.
This simple mechanical device works well and is very transportable/stable.

Step 2:

I used a cap from a cap gun (the plastic caps, not paper) and a metal tube that fits into the cap (piece of pen cartridge). It should be a snug fit.

Step 3: Holding Tube.

Then a tube that this piece could fit in well enough to travel back and forth. The pen cartridge should protrude from the holding tube by 1/2".

Step 4: Hurry Up and Weight.

Secure a weight to one end of the holding tube, this will be the striking end for the cap. Then take a lead fishing weight and drill a hole big enough for the pen cartridge to fit securely in. This will allow the fire to escape from the cap.Secure the weight to the end of the cartridge that protrudes from the holding tube. There needs to be a 1/32"gap between this weight and the holding tube.

Step 5: Make Your Case.

Ideally your weights should be of nearly the same diameter with the one at the cap end being thicker, for more weight.Then take yet another tube that is of equal length to your assembly that fits the cap side weight snugly. The sliding weight/pen cartridge should move freely. The whole assembly must fit in an egg, so experiment with the dimensions.

Step 6: Now for the Egg.

Now that you have your initiator, it's time to blow out some eggs! Peirce the egg at both ends and puncture the yolk. Blow into one end while over a bowl. Wash out the egg with soap and water. then let dry.

Step 7: Assembly of the Smoke/flash Portion.

Here is where I cheat. I buy flash cotton from a magic shop and smoke bombs from the fireworks shop.
I take out the core from the smoke bombs and make sure they are in powder form. I then take the powder and weigh it. Figure how much 25% of that weight and use that number to add potassium chlorate. This is an oxidizer and will speed up the burning process.
Now take the mix and add a wad of flash cotton. kneed the mix into the cotton until the cotton is completely engrossed in the powder.
Carefully place your initiator in first. Heavy end to the fat side of the egg.
Then begin to stuff the cotton in with a wire or small stick. When you feel the egg is nearly stuffed with cotton, top off with some of the powder mixture.
You can tape or glue/paper over the hole and viola!