Well paced, written and executed, a good horror/thriller to watch alone (in the dark) or with friends who like this genre. As always Sandra Bullock deliver a good amount of emotion and drag the viewers with her, delivering a pleasant rush of adrenaline.

I dont know if there is a book and to be onest i wouldn't be surprized otherwise, still if it is, i think that it's a good adaptation maybe a little longer and i would appreciated knowing more about the "creatures". To somewhat degree i have to say that it could be a sequel of "in the mouth of madness" where a similiar entity came alive after certain events. Again 6/10 worth to watch.