'Sea Fog'), also known as Mad Spider Sea,[1] is a 2020 Taiwanese monster thriller film[2][3] directed by Joe Chien.

[4] It stars Wang Yangming, Zheng Renshuo, and Ko Chia-yen, and follows the crew of a boat threatened by a dangerous storm and a colossal aquatic spider.

[2][4][5] During an attempt to rescue a tanker in a storm, a search and rescue crew witnesses a large shadow beneath the waves and is pulled into the sea.

Years later, lone survivor Ajie boards a boat which becomes lost in a storm, and must work together with his fellow crewmates to survive against both the weather and a number of creatures lurking underwater, including a giant aquatic spider.

[4] A trailer for the film was uploaded to YouTube on 19 August 2020.