Fungi

I think this is a Leucocoprinus, as far as I know. It's commonly found in house plants and lives on decaying matter. You definitely don't want pets and children to eat it. It's not directly going to harm the plant, but it can be a sign that the potting mix is breaking down.

You can pull the mushrooms out, but it won't get rid of the problem because the bulk of the fungus isn't the fruiting body itself. If it's time to repot, then you can try that, as it will remove the bulk of the mycelium. It doesn't mean the fungus can't or won't come back, though.