If you have ever been to a korean hair salon, you may have seen a poster with a picture of a squid on the wall. I could not find any information on the world wide web about "Cuttle Fish Ink".
However, there is a brand called "Squid Ink" or maybe known as O-jing-eo Ink-ku (오징어 잉크). The meaning of Cuttle Fish and Squid are similar in Korean.
Brand: Squid Ink Shampoo
Size: 1000 grams
Price: 18,000 won (about RM55 according to the website).
Here are two links I found to it on the internet Squid Ink HairDye
and Squid Ink Colour Treatment.
That's solves the mystery, right?