Mooshrooms are a special type of cow that are exclusive to the Mushroom Biome. They are similar to regular cows and you can even milk them… except you won’t get what you expected. Instead of milk, you get mushroom stew.
This is actually very useful as the stew can restore some of your hunger bar. If you find yourself in a Mushroom Biome, then you should definitely gather as many Mooshrooms as possible.