Have you ever cooked yourself some biscuits, but forgotten to remove them from the oven when the recommended cooking time has passed? What did you end up with? Yes, charcoal.

Charcoal is produced whenever you burn something, and being black, is very dark.
Indeed, there is no colour darker than black. Some people don't even regard black as a colour - more a lack of colour.
These people are known as intensely boring.

The darkest substance is found in deep space, where there is almost no light at all. It is space itself.
But man didn't make space. Aliens did.

The darkest manmade substance, therefore, is burnt treacle.

Try it out!