When you choose a "Super Secret Settings" Shader, sometimes, it can show a black horizon in the sky. It happens on most of the shaders, but a few ones doesn´t show this bug (Like the NTSC one), it even happens on the Spider view Shader!. Something to note is that the clouds are a bit darker when this happens, also note that the black horizon its still black on the "Invert" Shader.
Please force a crash by pressing F3 + C for 10 seconds while in-game and attach the crash report (
[minecraft|http://hopper.minecraft.net/help/finding-minecraft-data-folder]/crash-reports/crash-<DATE>-client.txt
) here.