What are these things?

[Magical Reef]

The first thing looks Luke some sort of shell-less snail and the other is a weird gorgonian looking crab. It was actually on a gorgonian that I bought and is now crawling around my tank it looks like a mix between a crab, a starfish and a gorgonian. I shot some brine at it and it grabbed it and brought it to its mouth similar to the way a sea apple does

 

[Reefing Madness]

Looks like some sort of Sea Slug

 

[sageharmon]

The second one is a Basket Star.
Very hard to keep alive in captivity, as it needs a constant supply of planktonic food. Rarely kept alive for long in captivity.
You can give it a shot, just be prepared to feed bbs or other small food items 4-5 times per day