Make the necklace with black sculpey. Make a base with aluminum foil first to put the clay over (so it doesn't break easily) and use a wire in the base where the hole to attach the chain is, again for durability. You can get a chain at a hardware store, or if you're lucky, a party supply store, dollar store, or craft store. (I know I've seen one recently but I forget where. ._.)
The chain on his pants looks like it's made of a bunch of similar rings, but you could probably pass with a bulky, intricate chain. Shop around at craft stores, where they have chains for necklaces, and you might find something passable. If not, try to order a bunch of rings like that in bulk online and build it yourself c:
The charm on the end you could make with sculpey, fimo, or if you picked out a smaller more realistic chain, you could find a charm where you bought the chain that would look similar.
