The way that feat is worded is begging for abuse. I mean, it simply overrides your type, whatever it is, it changes to animal. Hell, even nonsensical stuff like, you were undead, but you are still Animal type, because of the feat. Wha..? I do.. Eve... Wow. Yeah, seriously, you can be undead, but - hey! No Turn Undead, no Disrupt Undead, no nothing that works on undead will work on you, because you're no longer of Undead type, but still maintain the qualities, debatably - one could argue you lose them when you lose the undead type, meaning your - con kills you. Apply all the juicy animal-only templates that only cost gold...