It may not be the worst of times, but it is certainly not the best of times. The pandemic has no end in sight. The world is warming, the seas are rising and polar bears are barreling toward extinction. Also: taxes, the 9-to-5 workweek, the renewed threat of nuclear war.

As people looked for someone to blame besides themselves and all of humanity, a culprit emerged in the form of a fish, specifically the 375-million-year-old Tiktaalik (pronounced tic-TAH-lick). Our modern woes would never have existed if our ancestors had never left the water, the reasoning went. Tiktaalik’s four whispers of feet made the fish an easy target.

In 2006, the artist Zina Deretsky made a scientific illustration of Tiktaalik for the National Science Foundation. More recently her depiction of Tiktaalik as a pensive-looking fish poised to leave the water has become the foundation for a flood of memes.

In one, the fish is met with medieval polearms and premonitions: “If you see a Horrid Beast evolving, PUSH IT BACK IN.” The memes yearn to thwack Tiktaalik with a rolled-up newspaper or poke it with a stick — anything to shoo it back into the water and avoid our having to go to work and pay rent.

When Ms. Deretsky first saw one of the memes riffing on her Tiktaalik illustration, she felt she could commiserate. “Our world is a little bit difficult right now,” she said.

Scientists may never know exactly why fish like Tiktaalik and early tetrapods — vertebrates with four limbs — moved onto land, said Alice Clement, an evolutionary biologist and paleontologist at Flinders University in South Australia. “Was it to seek out more food, escape predators in the water, find a safe haven for their developing young?” Dr. Clement asked.