Is this mushroom harmful?

[ceropegia]

I just got this orchid (picture 1) the other day from a professor at my university. (I can't remember the name of it) and he said it would be a good terrarium orchid.

I just started two terrariums out of glass jars (about 8" in diameter) using some mulch and moss I collected outside. I placed the pot with the orchid inside the terrarium temporarily, since I wanted to keep it humid before I converted the terrarium to all-sphagnum moss.

Well, today I noticed this mushroom (picture 2..sorry it's blurry) growing inside the other terrarium, where I have a tiny maidenhair fern growing. It was a tiny mushroom (I removed it and a second one I found) only about 1/2" high, but I'm now worried that perhaps the orchid will grow mushrooms in the pot, and I want to know if those mushrooms are bad for it. Would they be bad for the fern?

I also noticed a few tiny snails (1 mm with spiral shells) in the fern's jar. Are these harmful too? I'm thinking of just throwing all the contents of both jars out and starting anew, but I wanted to check here first to see if there was any reason not to. I'm definitely going to sterilize the jar for the orchid and buy moss for it, but I want to know if I should keep the wild moss I collected in the jar with the fern and just leave it alone, despite the mushrooms.

Advice?