Babylon's Ashes
... that characters from several different science fiction media appear as an Easter egg in the episode "Babylon's Ashes"?
... that characters from several different science fiction media appear as an <a href="./Easter_egg_(media)" id="mwBlo" rel="mw:WikiLink" title="Easter egg (media)">Easter egg</a> in the episode "<b id="mwBls"><a class="mw-redirect" href="./Babylon's_Ashes_(The_Expanse)" id="mwBlw" rel="mw:WikiLink" title="Babylon's Ashes (The Expanse)">Babylon's Ashes</a></b>"?