In what could be described as the scariest thing that I ever experienced in almost 8 years of playing this game, a Phantom spawned above my dug out shelter in a Mesa Biome. The blocks between me and the night sky were ladders and a closed trapdoor.
What I expected to happen was...:
No Phantom spawning and scaring the ever living hell out of me
What actually happened was...:
Monster spawned and its sound queues almost gave me a heart attack.
Steps to Reproduce:
1. Do not sleep for 3 days
2. Shelter yourself in an enclosed space, with one block of the ceiling being a trapdoor.
3. Stand under the trapdoor as the night falls and stay there all night.
3. Phantom should be able to spawn like you are outside.
The described behaviour cannot be reproduced on 1.15 Pre-release 1.