WOW. I have never seen that before. I'm sorry I can't help you figure out what it is for sure, but it definitely looks like some sort of fungus. It is definitely not new sprouts. To be safe, I would isolate it from the other plants, but it shouldn't need to go outside of the house. Good luck, and I hope someone else on here knows for sure what it is :\

It looks like it may be what is commonly called the yellow houseplant mushroom (scientific name Leucocoprinus birnbaumii). It won't hurt you unless you eat it and shouldn't bother the plant at all. For cosmetic reasons though you might want to remove the mushrooms before they mature and reproduce and also change the potting mix so new ones don't sprout from spores in the mix.

Hi,
I agree with Donna. It looks like a mushroom and more than likely the spores were in the mix. Repot and get rid of them before they get too large and start to affect the symmetry of the plant.
Fred in NJ

Nice little mushroom cluster you have growing there. Donna is correct in the name, and it is fairly common. The spores are in the potting mix, but since it appears to be mostly peat, you or your mom will want to change it out. I would pluck it out just so it doesn't cause the leaves to grow out of shape. Since the mix is mostly peat, be real careful about not overwatering the plant while it is in your care. When repotting, use a potting mix with 1/3 peat, 1/3 vermiculite, and 1/3 perlite.

Barbara

Thank you! I have repotted it!

I'm glad I just had to repot, because I think that plant had the best symmetry