First things first, Paul offered me a free copy of this product, but after I read it, I went back and paid for it. I expect to make use of it in a few different ways and the price wasn't exactly going to break the bank anyhow.
The charts here are well-organized and useful. They include some options you'd probably consider mandatory for a horror game (like tentacles) and some things you might not have thought of (like acquired - a creature which steals limbs from previous victims). The same goes for several of the other categories. Some of the categories go pretty far-afield, like creatures which excrete urine or semen at will, but honestly those are both pretty horrifying.
For myself, I kind of see a couple of places where I can use this quickly. I'm running a Champions game were some of the villains are playing with magic they don't really understand. Using these charts to generate the creature will make it easy for me to then stat out the character. With the release of Horror Adventures for Pathfinder, there's going to be even more call for creatures and this might help me make them.
Overall this is a great collection of tables with some very inventive options as well as some of the expected options. It's a great product and I'm glad Paul suggested I check it out.