Lau extinction event
...that the Silurian Lau extinction event caused the Earth to temporarily return to a condition similar to how it was before multicellular life evolved?
...that the <a href="./Silurian" id="mwEeM" rel="mw:WikiLink" title="Silurian">Silurian</a> <b id="mwEeQ"><a href="./Lau_event" id="mwEeU" rel="mw:WikiLink" title="Lau event">Lau extinction event</a></b> caused the Earth to temporarily return to a condition similar to how it was before <a href="./Ediacaran_biota" id="mwEeY" rel="mw:WikiLink" title="Ediacaran biota">multicellular life</a> evolved?