What Is This Ugly Looking Thing!?

I saw this worm/slug thing in my tank today and it was just moving around on the rock. It moved like a caterpillar, taking the motion through the whole of its body before moving forward. It had really short tentacle type things coming from its mouth and it was a brownish colour. I quickly took it out of the tank and put it in a cup. When it was in the cup it occasionally extended a long grey tube from out of its mouth before pulling it back in. It was so disgusting looking.... it really freaked me out! Any help on identifying this thing would be really helpful.

 

look like a bristle worm to me, harmless+ good part of CUC+ great snack for some fish and inverts if caught

 

Not a bristle worm. Might be a peanut worm.

Check out this link.

http://www.chucksaddiction.com/hitchworms.html

 

I thought bristle worms were reddish/pinkish, so I agree it's not a bristle worm

 

bristleworms also have bristles or legs like a centipede, this one appears to be smooth, like an earthworm.

 

Ribbon worm....... Nemertea