The official Minecraft Wiki states that no hostile mobs spawn in the Mushroom Fields and Mushroom Fields Shore biomes. The phantoms break this game mechanic by spawning in these biomes anyway.
No mobs other than mooshrooms spawn naturally in this biome, including the usual night-time hostile mobs; this is also the only biome where mooshrooms can spawn. This also applies to caves, abandoned mineshafts, and other dark structures, meaning exploring underground is mostly safe.
Reference:
Linked issues
Comments
migrated
migrated
Confirmed in 1.15 versions randomly including base (1.15.0)
Confirm for versions stated, even as a duplicate, as the Official Minecraft Wiki's only source for information has been the Official Mojang logs for Minecraft, albeit the launcher news, the Minecraft.net website, or other sources BY MOJANG I am missing
Confirm in 1.14, 1.14.1, 1.14.2, and
in 1.14.3 as of changelogs as well as changelogs for 1.14.3-pre1 through 1.14.3-pre4
Yes the line spacing is intended, note the space for confirmation basis(s)