Context –
Image 1: In the movie Wayne’s World, the titular character says “A sphincter says what?” to confuse someone so that they say “What?” – implying that they’re a sphincter and embarrassing themselves. A sphincter, for those unfamiliar, is “a ring-shaped muscle that relaxes or tightens to open or close a passage or opening in the body.” with the anus a common example.
Image 2: Pearlfish are marine fish (Carapidae) that frequently live inside invertebrate hosts, including sea cucumbers. There have been a few documentary-type videos released highlighting pearlfish entering, exiting, and resting with their heads outside of a sea cucumber’s anus.
Image 3: The sea urchin crab (Echinoecus pentagonus) is a species of crab found across the Indian and Pacific Oceans that makes its home in the anus of sea urchins. This species was featured as an iNaturalist Observation of the Week in 2016, which is how I learned about it.