I have had mushrooms before in my house plants and i think it is due to the soil. I don't think it is really good or bad but I prefer not to see mushrooms, it makes me think my roots are going to get rot/fungus. I actualy saw some in my old planter and it was part of the reason I decided to transplant. I've had people tell me mushrooms are a sign of healthy soil but it seems to me that it would be a sign of too much moisture. and no, they are not magic. don't eat them and don't let any pets near them.