The picks and the ice cubes appears when you deal some damage on immortal version of Zushuka. So if you meet the boss there is nothing more on this place, except the boss itself. You won't find any additional monsters nor any additional objects.
But! When you see picks and the ice cubes it means that someone has dealt the damage to Zushuka and she already is somewhere in the cave.
As you can see on the picture below, when I killed Zushuka there are no picks anymore.
So you will see it only during her immortal stage and probably at the beggining when blue-haired moral version appears: