I have an idea that involves an intelligent construct swarm, and I'm wondering how to calculate the CR in this case, because it seems to me that adding swarm traits to construct traits could be particularly nasty.
This is just an idea I'm toying with, so I didn't want to clutter the rules forum with it. The idea is a set of intelligent silverware whose "special purpose" is to feed guests. If you touch the silverware, you are compelled to eat (ego save). If you oppose the purpose (by not eating) you become its "enemy" and the silverware attacks as a medium swarm (CR ?).