Remember diazomethane? The explosive methylating agent?
I just wanted to give you an impression of how dangerous it is =P
Not only is it highly explosive, it is both highly acutely toxic, as well as a suspected carcinogen*
Diazomethane is a shock explosive, and contact with anything but the smoothest surfaces is highly dangerous. Synthesis of diazomethane isn’t difficult, chemically speaking, but is very dangerous. Special ‘diazomethane synthesis kits’ are needed, which contain highly smooth glass (ordinary glassware is too rough and could cause it to explode).
As well, it is synthesized as a gas, which is when it is at its most dangerous and toxic, so these kits are designed with condensers attached so the gas never gets to escape. The entire synthesis is conducted from behind a blast shield also.
Even when chemistry is dangerous, it does it in some pretty cool ways =)