Have you ever wanted the cordyceps fungus to infect the cows in Minecraft? Well now it can! This addon replaces the red mooshroom texure with a version of the default cow with a mat of mycelium growing on it. The brown mooshroom has been left unchanged in base texture for the sake of having a different variety of cow. Put this addon in your resource pack folder and voila, infected mooshrooms.
Credit to u/TheDarkShadow36 on Reddit for the original concept.