Seashell Shark

Seashell sharks begin life without teeth. As they grow, they choose seashells from the sea and set them in their mouths, where the shells take root and grow whiter and tougher with the years, becoming the teeth the sharks use to tear apart prey stronger than themselves. This leaves infant seashell sharks very weak, but adults are overlords among sharks, and a group of them, individually and collectively, far surpasses a group of sea spiders in strength. Near the Earth Trench’s black oil off an unnamed island, a huge group of seashell sharks attacks a party of oil collecting Gu Masters; the sharks are too large to move easily through the black oil, and the Gu Masters feed them to the oil, which devours them slowly and would in time corrode all their flesh, bone, and blood into new black oil. Fang Yuan has the trapped sharks dragged out, most of them still alive, judging them usable Gu materials he can clean of the oil; he has already designed a Gu recipe that uses seashell sharks as its main material. ^{ch. 1655}

Later, at the Earth Trench in Dragon Whale Paradise, Fang Yuan finds a group of seashell sharks swimming near the black oil, and he conceals his presence and passes them rather than engaging. ^{ch. 1893}