I’m sure you’ve heard this one before:
In the darkest places of the world, ancient evils slumber.
This trope is common to fantasy and horror. For your challenge today, take this trope and give it a twist.
To help you get started, try making a list of everything this trope makes you feel. Then make another list of dark things or places. Keep going on the lists, with no regard to whether an idea is good, bad, or weird. Just keep writing.
After about five minutes of that, create your entry!