Need help identifying

Hey guys,

I was cleaning up my engine bay on the weekend and noticed there is a sensor coming off the exhaust side of the turbo with a single cable coming off it. I then noticed that it doesn't actually go anywhere.
Is this my o2 sensor and does it need to be connected? And where does it go? Will it cause problems if it's not connected?
By the way, it's a 3SGTE.
I would have taken a photo to post except it's not easy to do.

Hopefully someone can shed some light for me.

Yeah it is. Ok so O2 sensor. What next? I'm guessing it's not bad that's it not connected, il just be running real rich? Where is it supposed to go to? There is another cable going into the engine bay near the side mount that's also not connected. Do you think they are supposed to join?

The o2 sensor is only a inch or two from the turbo.
There is also a cat temp sensor further down witch wont matter. Most people with after market dump pipes dont bother putting it in.