Bamboo Charcoal Bread

I was in JB for a printing press check this afternoon. My colleague and I stopped over at one of the shopping mall while waiting for the printer to get ready for the machine for press check. I entered to this Lavender cake shop and this particular black thing captured my eyes. It was a black colour bread made out of bamboo charcoal. It is soft, comes in 3 slices a packet, taste normal except that when you poo, it's black : p