Mozuku is a type of Okinawan seaweed. It is kinda slimy, but the taste is mostly salty and not too ocean-y.
Recently, the once-a-month farmer’s market in my village had free mozuku, as much as you could stuff into a plastic bag. At first, we felt a bit timid… neither my husband nor I have actually prepared mozuku ourselves. We have eaten it several times as part of a teishoku (set meal) in Okinawan restaurants, but it is not something that I really go out and buy. But who can turn down free? So my husband got a baggie and got in with the ojiisans and children to fill up.
I think the best way to prepare mozuku is to fry it in tempura or add it to okonomiyaki (the Okinawan version is hirayachi: ヒラヤーチー). It is also possible to prepare it as mozuku-su, which is just prepared with vinegar.
Mozuku-no-hi もずくの日 (mozuku day) is the 3rd Sunday in April.