Quiz -What is shown in the picture

[anglfish]

I have some stuff growing and crawling in the tank and have no idea what it is. So I took some pictures (finally got my camera back) and post it as a quiz for you.
Hope you can help!

(1) Fire Worm? Is that a good thing or bad thing? Attachment 553

(2) Bubble Algae? should I remove it? or only if it spreads more? how to remove it? Attachment 554

(3) some sort of coral? or what? Attachment 555

(4) feather duster? Attachment 556

(5) haha no idea at all ... Attachment 557