Benandonner is a giant from Scottish folklore, often associated with the legend of the Giant's Causeway in Northern Ireland. He is said to have lived in Scotland and challenged the giant Fionn mac Cumhaill to a duel. According to the tale, Benandonner built a causeway across the sea to reach Ireland. When Fionn saw the size of Benandonner, he devised a clever plan to avoid the confrontation. The story highlights themes of bravery, cleverness, and the clash between giants in mythology.