I keep telling you guys, it's BIG FOOT<img src=icon_smile_big.gif border=0 align=middle>
Or... It could be a Bobcat, I have heard these large cats make this sound and is does sound like terrible scream. Bigfoot makes this noise too, so some say.
I have also heard this freaky scream and seen deer and other animals haul butt? Who knows until you see what's making the noise.
KEEP HUNTING THE GREAT OUTDOORS & GOD ALIVE, PASS IT ON!