noun. Such a non-youthful lifeform, like a loving grandpa or Biblical snake demon.
Real citation: "as for the criss-cross features, are those paleo-critter tracks? if so then it probalby means that we are looking at the bottom of a layer."
(Sept. 1, 2008, Looking for Detachment, http://highway8a.blogspot.com/2008/07/friday-field-photos-wheeler-peak.html)
Made-up citation: "A paleo-critter ate my kitten! I guess the old always destroy the young, like that time Bob Barker tried to devour Hannah Montana organs-first."