For Day 15, i didn't use the prompt which was Mysterious, solely because it is easier to think of Mysterious than draw something Mysterious. I instead did a smaller sketch just to make sure i don't burn out and fizzle away.  What i chose works better on a larger scale. I tried to interpret a branch with the dew along the spiderwebs (done in 10 minutes max.)

I used Fineliner 0.1 and 0.2

Enjoy!!