This is a foam spraying gun used by the bio-hazard containment forces. These are seen toward the end of the film being held by the white 'hazmat' team standing behind Daxus as he finally captures Six.The small image here is a screen shot from the film. In the movie, these are never actually seen put to use. I do have a publicity shot showing them in use though. Here you can see Six being covered in foam by the two guns. The guns simply have a tube going through them connected to source of the foam. There's a spring-loaded trigger on the gun, but it doesn't actually do anything. Foam flow is completely controlled off camera at the source.
