The line —
"You could almost sing, 'Seaweed, seaweed, swaying with the waves,' and dance through the spray without a care."
— is a playful reference to the Chinese internet meme "海草舞"(Hǎicǎo wǔ - Seaweed Dance).
It comes from a viral song called "海草舞" ("Seaweed Dance") by Xiao Panpan (小潘潘) and Xiao Fengfeng (小峰峰). The lyrics repeat "海草海草,随波飘摇" — "seaweed, seaweed, swaying with the waves" — and it became hugely popular on Chinese social media around 2017–2018, often used in short videos and dance challenges.
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I pluck this from The Cube Queen's Apocalypse Feast, Volume 3: A Torrential Banquet, Chapter: Vice President Jing Shu's Assessment Begins