Conquistador3
Le Comte de Frou Frou
A few years back I saw pics of guys throwing dead saw crankcases into the fire to watch the magnesium burn. Not sure if that would cause dangerous runoff though?
One of the first things a chemistry student (I was one many many moons ago) learns: the two most dangerous things when burning magnesium are
1)Water and CO2 extinguishers will just make things worse... actually water will make things much worse
2)The worst risk for your health is looking directly at the flame without welder's googles or another form of UV eye protection
Assuming magnesium is in pure form or very nearly so the byproducts are just magnesium oxyde, which can help with indigestion, and a lot of energy in form of light and heat.
Magnesium alloys used in dies usually include small quantities of aluminum, manganese, zinc and occasionally more exotic metals... nothing in such quantities as to be harmful unless directly inhaled.
Of course this is not a behavior your local authorities, especially professors, are likely to condone unless carried out for didactic purposes under controlled conditions...