Shachiku Tamer, Kawaii Slime no Okage de Mujikaku na Mama Musou Suru: Ukkari Kokunai Toppu no Haishin ni Utsuri Konde Saikyou ga Baremashita

In the modern world, "otherworldly dungeons" suddenly appear.
Dungeon exploration streams by glamorous streamers have become incredibly popular, and dungeons are now the world's biggest form of entertainment.
Meanwhile, Yamaoka Eita lives a life of corporate slavery, completely detached from this world. His only pleasure is playing with his pet, a slime monster from the dungeon. However, the floor Eita and the slime were playing on is an uncharted level, barely accessible even to top streamers—!?

(Source: Ultra Jump, translated)