An allegedly <a href="https://en.wikipedia.org/wiki/Coso_artifact" id="mw5w" rel="mw:WikiLink" title="Coso artifact">500,000-year-old rock</a> is discovered near <a href="https://en.wikipedia.org/wiki/Olancha,_California" id="mw6A" rel="mw:WikiLink" title="Olancha, California">Olancha, California</a>, US, that appears to anachronistically encase a <a href="https://en.wikipedia.org/wiki/Spark_plug" id="mw6Q" rel="mw:WikiLink" title="Spark plug">spark plug</a>.