The world of wearables gets wider - and weirder - at CES

At the International Consumer Electronic Show in Las Vegas, wearable tech is going way beyond the wrist, and in some cases, the limits of reason.

To wit: the robotic spider dress, with eight legs that bristle when someone gets too close.

"I have two proximity sensors right here, and when someone walks too close to me, the spider legs will come out and act in aggressive mode almost saying back off," Whitney Heleker, a model wearing the dress, told CNET.com's Kara Tsuboi.

The Belty smart belt is motorized and can cinch and expand to help you control your waistline -- or at least be unable to forget about it. And to control your gadgets around the house, slip on a ring from Logbar.

"You connect this with your smart device," Logbar's Momoko Matsuzaki said. "The gesture will have you play the music, skip songs, adjust the volume, take photos, tweet."

There are also wearable devices that monitor your health well beyond heart rates. The Linx IAS concussion sensor slips inside a cap or headband to record how many head impacts an athlete might receive during a game.

For injured athletes, a new device from Neurometrix helps them manage chronic pain around the clock without medication. The band, worn around the knee, is connected to a smart phone.

"It basically stimulates the nerves in your calf to release natural pain-relieving chemicals in your brain, blocking the pain in your spinal column," Neurometrix's Frank McGillin said.

Then, there are some wearables that stand out for their shine and sparkle. Misfit teamed up with Swarovski crystal to make a fashionable fitness tracker. Studded with crystals, the device measures your daily activities, the quality of your sleep and syncs with your smart phone.