It's called Vantablack. It's made up of carbon nanotubes. Vantablack absorbs 99.965% of light; the nanotube construction traps the light until it becomes heat.
Isn't that interesting?
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Technically black holes, they're essentially stars so dense and large that the gravity becomes so intense sucking in all light it produces. Were only able to detect them from the large quantities of super heated fast moving objects orbiting and being sucked into said black hole. Although I was not aware of the substance which you speak it is pretty interesting