What's going on is there is a fungus growing in your medium and it's decided it's time to reproduce. This is not an unusual occurrence. You can remove the mushroom but the fungus will still be in there.
Ignore it and enjoy the new mushroom/s next time or re-pot. I usually just leave them alone.
Those fungi that form symbiotic relationships with plants (aka mycorrhizal associations) are not known to produce mushrooms, and pathogens similarly generally don't either. It's probably just feeding off of the soil, which for now is harmless to the plant but it will somewhat help speed up the breakdown of the soil and mean you'll have to repot sooner over later (though that sooner may still be a few months to years off).