This is a particularly strong Necromoph that cannot be killed. Just like the Hunter from Dead Space, it will regenerate any lost limbs. Encountered in chapter 14, you'll have to deal with it all the way until the end of the game in chapter 15. It is highly suggested that you upgrade your stasis fully before reaching chapter 14. If you need some time to work, cut off one of the Ubermorph's legs, and then an arm. It will try to regenerate after this point. This is the part where you want to hit it with stasis. Fully upgraded, it should give you 10 seconds of free time.
Note that there is a glitch in this game that allows you to get rid of the Ubermorph. In the very last room before you reach the end, there should be a massive fan blade spinning. Push the Ubermorph into this fan blade to rid yourself of him/her/it.
Added by: Forgoten_Scars Feb 26th 2011, ID#3664