Put the legions dog brain into rex and he gets 100////0 life..
Thats 100 life and 0 max life.. he cant be healed and he dies very fast.
he had like 400 life before i put te brain in him..

It was no bug either.. someone messed it up cause i saved before this quest and i did it 3 more times and the same outcome.

Obviously this quest was not tested even 1 time...
:(

And i cant be too sure but the damge brain seemed to make his damage weaker as well...
(since it dosnt tell you his damage i dont know)

So i chose the running brain, which is useless *sigh*

I just recently did the quest for rex's brain.... go to Gibson scrap yard.... you aquire the new brain for either 700 caps, or if you have high speech you can aquire it free....

it will give you the added perk for rex of having a much more deadly attack served up by rex.... VERY useful when your overwhelmed by legion