They are the particle effects.
see? Particles. Fuckloads of particles!
I've also managed to make fire, bubbles, dust, vent coolant mist, chocolate rain, smoke, etc. and a variety more. They are included in 6D. Its a shame no one ever really uses them. The aurora system is primitive but effective in the right hands.
In detail, you can make a small and easy script to handle the emission of sprites from a point entity, or bind it to a position, like a monster. (flaming zombies in goldz0rz for example
) They can also animate or choose a frame to be used, which can be random. Just about anything with a number can be set to random, so making effects is easy and variant everything.
I'll add to the original script document and release it too, it was inconclusive and there are more commands than it lists. lame.