What can I do about this? (Sorry about the picture)

Yes this is really how my roommate left my guest bathroom. I don’t even know where to begin. I saw something online saying to pour vinegar and baking soda dissolves feces. I even considered pouring muratic acid on it to break it down. A little bit but I need to clean this up a bit before the plumber gets here and have genuinely never seen anything so extreme in my life