The monster

Hello, There is a monster under your bed
But I know you don't
And when you least suspect it
I shall sink my claws into you

I've sat at wait for so long
Hidden plotting my next move
The air down here
So cool and tempting

And at last there you go
Naively you've let your foot stray
Stray way to far beyond the edge
And I can see your ankle

I shall take my prey
And once I have the foot
I shall not stop
Not till I eat the rest

Who is "ouch, you damn cat?"
That's not me
I'm the monster under your bed