From BloodBlood, occupying slot 7. Caleb holds his lighter to it and uses it as a flame thrower. This sets the victim on fire, causing damage even without needing to continue to fire the weapon. Its range is limited, but the alt-fire turns it into a molotov cocktail, setting objects and people ablaze in a rather large splash radius. Monolith Productions warns players not to "try this at home".
Though the concept behind the aerosol dates back to the 1790 the first can was invented in Oslo in November 23, 1926 by Erik Rotheim. It was not until 1939 that a patent was filed for a disposable aerosol spray can and not until 1941 and beyond that it began to attain popularity. This makes its inclusion in Blood, retroactively dated as 1928 in Blood II, somewhat historically dubious.