nightmarecraft-1.16.5-1.0.4.jar is a release file of the Minecraft mod project-538463, made for Minecraft 1.16.5. It was published on November 14, 2021 and is 585 MB in size. For the full description, screenshots and every other version, visit the project-538463 mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.