This is my thirtieth illustration for Inktober 2021, for the prompt "slither".
When I started making this one, I wanted to add a bit more texture to the walls and the tentacle, but as I added each layer of light/shadow, I started to embrace the simplicity of it. In the end, just a little bit of airbrushing was all it needed.
Just one more to go and this year's Inktober project is officially complete! Time-lapse below: