Bitise gave a contented plip. Vicineko scooped the slime up and twined her fingers through Fischl’s, both allies and friends in that quiet, starlit moment.

The work you're likely referring to is the high-quality 3D animation titled created by the artist

is a niche fetish-themed pairing found in some adult fan communities. These works usually depict Fischl interacting with in-game slime monsters in a comedic or explicit manner. Mainstream review platforms do not catalog such content due to its explicit nature.

You can find official updates and work-in-progress snippets directly from the animator on Vicineko's X (Twitter)

Imagine Fischl, with her raccoon dog companion Oz, encountering a slime in the wilds of Teyvat. This slime, let's say, has been imbued with Electro properties, perhaps through Fischl's intervention or a natural occurrence. The result is a fascinating fusion where Fischl and the slime merge or form a symbiotic relationship.