Bai Huan Die

南海蝴蝶
　　常有人浮南海，泊于孤岸。忽有物如蒲帆飞过海，揭舟。竞以物击之，如帆者尽破碎坠地。视之，乃蛱蝶也。海人去其翅足秤之，得肉八十斤。啖之，极肥美。”或云，南海蝴蝶生于海市，其形态变化万端，又名‘百幻蝶’。
　　——《岭南异物志》

Southern Sea Butterfly
Someone once sailed in the Southern Sea, and moored at an island. Suddenly there were something looked like a thin sail flying across the sea and toppled the boat. The man hit something at the sail-like creature, and it was broken to pieces and fell to ground. The man looked at the creature, found that it was a giant butterfly. It weighed 40 kilograms even after its wings and legs had been removed. The man ate it, and it was very tasty.
There is another saying that this kind of butterflies were born in mirage, and they can take on thousands of forms.