They had at least one fossil of one of these critters at the Cleveland Museum of Natural History when I was growing up... it mesmerized me.(image from the old standby online reference) When I saw the following photo from Picture is Unrelated a moment ago, my first reaction was "That has got to be shopped." Then "waitaminit... that looks familiar. Was it um... eurypterid?" I don't know if it's a mock-up for a museum or something, but it looks right to me.Whether it is or isn't, my memory freaks me out sometimes; occasionally I get to the end of the day and can't remember whether I've eaten or not. Yet somehow "eurypterid," correct spelling and all, bubbles up with barely a pause, 35 or 40 years later.