Voir Demon Slayer: Kimetsu no Yaiba (Original Japanese Version), Season 1 - Episode 15

Their next destination is to the north-northwest. Tanjiro and Nezuko head to Mount Natagumo along with Zenitsu and Inosuke. The mountain is full of spider webs and is swarming with spiders... Leaving behind frightened Zenitsu, Tanjiro and Inosuke make their way up the mountain, where they encounter a fellow Corps member entangled in spider webs.