organism

I see a few different organisms and I’m not sure what’s good and what’s bad. Please help ID. I believe the stuff on the glass is pineapple sponges (good or bad?) but not sure on the other stuff

I’m having trouble figuring out what this thing is, a couple of them came on a clump of spaghetti algae I had purchased. I will post some pictures down below. Sometimes I will notice them swimming through the water column like a jelly fish when I shut off the pumps for couple minutes to feed my...