Monster!

What is it?

         
I live down in the basement,
I creep and I crawl,
If I'm in front of you,
You won't see me at all.

With teeth to cause bleeding,
I am biding my time,
Picking the right moment,
To commit my crime.

I have sharp claws,
To assist my teeth,
If these aren't enough,
There're more underneath.

I have very keen senses,
Especially hearing and smell,
I can hear your movements,
And track you blindfold, as well.

I have a long tail,
Perfect for wrapping around,
And when squeezing life out,
I don't make a sound.

I have two cold, black eyes,
Dark as the night's sky,
Now, you are left wondering,
What nightmare am I?

I am a most ambitious rat,
Bet you never thought of that.