Priapulus caudatus
... that penis worms very similar to Priapulus caudatus created trace fossils in the early Cambrian period?
... that <a href="./Priapulida" id="mwAf4" rel="mw:WikiLink" title="Priapulida">penis worms</a> very similar to <i id="mwAf8"><b id="mwAgA"><a href="./Priapulus_caudatus" id="mwAgE" rel="mw:WikiLink" title="Priapulus caudatus">Priapulus caudatus</a></b></i> created <a href="./Trace_fossil" id="mwAgI" rel="mw:WikiLink" title="Trace fossil">trace fossils</a> in the early <a href="./Cambrian" id="mwAgM" rel="mw:WikiLink" title="Cambrian">Cambrian period</a>?