We've shown you how to make smoke pellets, and they work very well, but they don't have the kind of instantaneous effect that we like to see if we're winged vigilantes of the night. If your enemies have you cornered, and you need to escape through a cloud of smoke, here something that might help you.
Granted, it's tough to lug around, but you'll kick yourself if you need it but don't have it on hand. The Dark Knight would certainly have it handy. It's actually not even smoke. Instead, you take a little liquid nitrogen, and a little boiling water. Combine them and you get an exploding cloud of vapor — steam.
The liquid nitrogen is acting as a "tracer" for the steam. Many of us have put our hands above a pot of boiling water and felt how hot and humid the air was, but seen only wisps of steam. When the boiling water is poured on the liquid nitrogen, the water cools and condenses quickly, becoming more visible than it would otherwise be. So we get a huge cloud of cool fog, instead of transparent wisps of steam.
This is not something to be attempted without proper ventilation. There is some nitrogen mixed in with the water, and if the fog doesn't clear quickly, the nitrogen could displace enough oxygen to suffocate people — as we saw in this horrible clip in which party promoters put liquid nitrogen in a pool and nine people fainted from lack of oxygen.
The difference in this experiment is not only the persistence of the cloud of fog, but its contents. Nitrogen vapor is relatively dense and tends to creep along the ground, which is why it collected in the pool. Water vapor will be the thing making its way into the sky. The eruptions really is, mostly, a cloud of water droplets instead of just nitrogen vapor. So as long as there's a bit of a wind blowing, feel free to make your getaway. The people behind will survive. This time.