Ripper is located in the vampire nest deep within the mines located in the northeastern part of the Mountain Pass. It is highly recommended that you bring an escort if you cannot kill the creatures there on your own (approximate strength being at least one step above chobos and zombies found in the areas around Freedom City, more for creatures on the lower levels).
The easiest way to get this mutation is to follow the path out of Lurleen until you hit a washed out bridge, then climb down into the river. Follow the river until you go over the waterfall, then follow the path of V's until you hit the mines being careful to avoid any hostile yetis. Once inside, use lmap to find the underground river, the ripper mutation will be just across that in an area labeled "Vampire Nest". The vampire bats there are hostile, but you can mutate quickly and escape or just suicide once you have the mut. You may want to bring some light with you though, as the second floor of the mines is pitch black.
This mutation grants:
+1 to fists +2 to climb -5 to locksmith -4 to craft -3 to repair -3 to medic -1 to pilot -1 to chemistry Ripper claws replace fists (Deals slash damage and can cause bleeding) The ability to and using your claws Can no longer normally
Your fists turn into ripper claws which are better then your normal fists and do slash damage instead of beat. While it is an advantage for you, it is bad for others. You can jerk off other people for a bit of damage. Ripper claws also have a high crit rate and will often fatality.
You can't wank anymore but that isn't a horrible loss. Also it becomes harder for you to get into the brainier things in life without quite a bit more grinding to make up for the losses from getting Ripper.
He/She has huge fucking bone claws sticking out of his/her arms.