No, it wasn't that. Actually mushrooms and fungus do not belong to Kingdom Animal or Plantae. They are Kingdom Fungi, and they feed directly on dead materials.
Plants only feed on what the fungi leave behind in the ground.
What do vegetarians think about that ? Is it edible or not ? Especially considering that fungus is actually some of the most efficient lifeforms around as far as converting food to body mass metabolisms.
To be honest I am a complete omnivore with a preference for meat; I am rather curious as to what drives some people to eat vegan though. Personally I have never felt that much compassion for anything dead on my plate other than to hope it died cleanly.