The name is Attié: 'biékô' means chili and 'sseu' means water, so biékosseu is literally chili water.
A fiery pepper-forward sauce, built from crushed chilies, onions and tomatoes, simmered with dried fish or snails until thick and glossy. It's poured over pounded plantain foutou for a meal that leans hard into heat.
Why it's made this way: Biékosseu comes from the Attié (Akyé) people of south-eastern Ivory Coast, around Adzopé in the Mé region, where a chili broth with dried fish or snails is a practical way to make a little protein stretch over a large mound of foutou.