Release the Kraken!

What happens when you combine NH4Cr2O7 and HgSCN and expose it to fire? A portal to hell opens up and the most dreaded denizen of the deepest slime is awakened. Whatever these chemicals are, they are dangerous, and the reaction is even more dangerous, so don't ever do this. But it is a guaranteed way to make a class of children yell "Kraken! Kraken!" no matter what their language. (via Geeks Are Sexy)