Okay, so I'm a chemistry student, and occasionally, I come across stuff that is really quite seriously cool.
This is one of them: Chlorine triflouride.
Amongst its many (mainly explosive) properties, it is a more powerful oxidant than oxygen itself.
This can lead it to setting fire to stuff you would usually think is pretty inert.
Like asbestos. And wet sand. And reacts violently with water to produce hydrochloric and hydrofluoric acids, both of which are noted for their, kind, gentle natures.
The fact that this stuff exisits is really quite cool (setting fire to cement? the mind boggles) but I would not want this in the same building/ city as me. And thats before you start reacting it up in the lab - then the shit gets real.