yeah, I've seen the Thing about 1000 times, ; ) . Someone already posted but since I got it, I'm going to post anyways, just gimme a little bit.
P.S. watch sequential pictures redub of the Thing. It is freaking hilarious, especially to anyone who knows the lines. You can find it on YT. Also, your riddle didn't suck, but the video snippet gave it away.
I'm there for your journey
Here to show if you are a hero
I always got your back
and true respect is what I give to you
remove me you are normal
destroy me you will be defenseless
If you had omitted either one of the last two lines, I think that "penis" would have almost been a valid answer. Depending on how you interpret the lines, and/or define "normal", it may still be a valid answer...