Crazy Cactus

Insanity has always seemed to me to be a relative term...who's "crazy" and who's "normal" are about the most subjective determinations one can make about another, fauna or flora.  This cactus's defences seem to have been conjured by a mad God, or by forces of evolutionary nature that appear incomprehensible.  I'm certain, however, they must have been designed to address some special need or shortcoming.