Pharaoh’s snakes or Pharaoh’s serpents are a type of small firework in which a lighted tablet exudes smoke and ash in a growing column which resembles a snake. The modern version of this firework is the non-toxic black snake. Pharaoh’s snakes produce a more spectacular display, but they are toxic so now this firework is only produced as a chemistry demonstration. If you have the materials and a fume hood, you may wish to make your own Pharaoh’s snakes.
Black snake and Pharaoh’s serpent are two similar types of firework.
After being lit, both fireworks begin to smoke and spew out ash resembling a snake via an intumescent reaction. They stay on the ground and do not emit sparks, flares, any form of projectiles, or any sound, but may release smoke.
Sodium bicarbonate which produces carbon dioxide gas, and sugar forming carbon containing ash, are common chemicals used for the black snake demonstration. Other sources report the contents as “a nitrated mixture of linseed oil and naphthalenes”. – Wikipedia