Well, not trumpets, they are livebearers. Mystery snails lay eggs above the waterline in larger yellow/orange egg masses. Not "pond/bladder snails", IME they lay flattish jelly like small egg clusters.
I'm not sure what that may be. Did you get any new plants, or new wood from a tank or "wild" waterway (rather than dried out at lfs) that might have come with something else?
Maybe someone else knows...