It was laver bread (made with seaweed) from an old friend in Wales.

I regularly eat laver bread.

To us, the black laver bread looked dreadful, poisonous, but we understood and respected that it was something Welsh, something special.

When I was a schoolboy in Cornwall, helping with the milk round, I tried to augment my pocket money by scraping laver bread off the rocks.

Laver is used to make "laver bread" in Wales where it is known as bara lawr; in Korea, gim; in Japan, nori and aonori.