Cartoon image from the always-bizarre Uncyclopedia, assumed allowed under Fair Use and perhaps even Unfair Use (but who knows what the second one?)
Dancing skeletons from a 1493 woodcut by Michael Wolgemut, assumed allowed under Fair Use. Europeans considered many things up for grabs in that decade.
Image of crowd of scientists taken from Google search. It is a screen cap of John Oliver’s show on HBO, assumed allowed under Fair Use.