The build up to that horse rumble was pretty awesome. The brown horse gives the white horse a look of 'watchu lookin' at?' and then it is ON! 2 thumbs up and 5 stars.
So apparently there was a mutant horse that was considered for addition into S.T.A.L.K.E.R. Shadow of Chernobyl. It looks like this. Enjoy your nightmares. edited to fix the picture, it'd gotten small and difficult to make out AND WE CAN'T HAVE THAT SORT OF THING WHEN WE'RE TRYING TO LOOK AT HORRIFIC MUTANT HORSES, CAN WE NOW?!