This is really early in the game, and maybe not the strangest thing I've ever seen, but it amused me at least:
Due to a lucky early mission, I got a recharging laser before I could buy even niners, which led to the amusing scene of someone using a laser while others were still using muskets. I misjudged a shot, and my gal with the laser got a musket ball in the back of the head, she survived and was still conscious, even killed a zombie before fainting, but it emphasized the laser/musket thing.