Can't really tell from the pic but if it came on a filter feeding coral it could be a filter-feeding type of brittle star. I've had those come on corals as well. They stick their arms out into the current and collect particles using fine hairlike structures on the legs. They tend to have the same care requirements as the corals they came in on. Not particularly hardy if that's what it is, but equally harmless. The worm is a peanut worm I believe. Again, totally harmless.

I thank everyone for their replies, it helped all lot :)