Inside the Tentacle Cave

Inside the Tentacle Cave (淫靡な洞窟のその奥で) is a Japanese web light novel series written by Umetane and illustrated by Akufuro (volumes 1–5) and Tsukineko (from volume 6 onwards). Umetane first launched the novel on the user-generated novel publishing website Shōsetsuka ni Narō, in the Nocturne Novels male adult section, in August 2013, and Kadokawa Shoten started releasing it on digital volumes in November 2015. A manga adaptation, illustrated by Abi, started on Nico Nico Seiga and ComicWalker websites' section Comic Vamp in December 2021. The manga has been licensed for English release in North America by Seven Seas Entertainment.

Light novel
Written by Umetane, Inside the Tentacle Cave started on the user-generated novel publishing website Shōsetsuka ni Narō, in the Nocturne Novels male adult section, on August 3, 2013. Kadokawa Shoten started publishing the story in digital volumes, with illustration by Afukuro, on November 6, 2015. Starting with the sixth volume, the artist changed to Tsukineko, and the series has been released under the title Inside the Tentacle Cave: After Disorder (淫靡な洞窟のその奥で After Disorder). As of December 8, 2023, 18 volumes have been released.

Manga
A manga adaptation, illustrated by Abi, started on Kadokawa Shoten's Nico Nico Seiga and ComicWalker websites' section Comic Vamp on December 10, 2021. Kadokawa Shoten has collected its chapters into individual tankōbon volumes. The first volume was released on June 6, 2022. As of October 6, 2023, four volumes have been released.

In March 2023, Seven Seas Entertainment announced that they have licensed the manga; it will be released under its Ghost Ship mature imprint starting on October 31 of the same year.