Multicolored fires are ranbow flames made by a concoction of chemicals. This fad appeared about the same time as psychedelia in the muddle world and can still be widely found today (like in Hogwash). The chemicals wizards use to create these flames give off a gas when burnt that induces hallucinations. As a result 25% off all wizards 'magic' is really their own sad delusions. Aside from hallucinations the gas can also make you very suggestable making the claims of magic absolute in the inhailors mind. If someone claims to have immupetised you while you are under this fires influence you'll belive it.