I made this necklace last Halloween, and wear it on a regualar basis. It is seriously my favorite necklace ever! And its 3D & shiny all over, so it catches lots of attention.

Just cut a necklace chain to your desired length, and attach a lobster-clasp closure. (I used a gunmetal color snake-chain on my favorite)
Then take your spider and safety pin. Heat the pin with a candle and poke a hole through its bottom, as close to edge as possible. Insert a large jumpring in the hole. Put chain through jumpring. Done!

(You can buy these hard-3D glitter spiders at most convenience stores, like walmart, a pack of 8 for $2)