It never fails: I’m lost in the supermarket, searching for turmeric ginger tea, when the benign ocean of muzak that’s been rolling through the store in soft waves suddenly pierces through my consciousness. Just like that I find myself singing under my breath to John Denver’s “Country Roads.” I can’t help myself. I can’t stop. By the time I’m back home, unloading the groceries, “Mountain mama, take me home, Country Roads,” is on endless repeat inside my hippocampus.

These songs—usually fragments—that you can’t seem to stop from continuing to loop through your brain, are called earworms, and per Psychology Today, researchers refer to the phenomenon as “stuck tune syndrome,” or “involuntary music imagery (INMI).” It turns out, these musical monsters start in the part of your brain called the auditory cortex where musical memories are stored, and not the hippocampus where learning and most other memory banks reside.

But why? Although scientists are spellbound by these auditory events, they still don’t know why they occur. And according to Psychology Today, 97 percent of people experience an earworm at least once a month. You can learn more about what researchers do know about earworms at The Kennedy Center’s site, what kinds of songs are more likely to worm their way in (and how to keep them out) from this New York Times article, “Why Can’t I Get This Song Out of My Head?”. But like an earworm, researchers aren’t giving up. In fact, earworms may actually be the key to becoming a better singer, one with perfect pitch!

If one of these little charmers hasn’t bored its way into your brain yet, then in the wicked spirit of this ghostly season (and with apologies in advance), here’s a Halloween earworm guaranteed to haunt: “The Hearse Song,” as performed by Carl Sandburg from his collection of folk songs, “American Songbag.” The earliest version of the now infamous verse, “the worms crawl in, the worms crawl out,” is found in the Gothic horror novel, “The Monk” by English writer Matthew Lewis, whose lines went: “The worms they crept in, and the worms they crept out and sported his eyes and his temples about.” Supposedly first sung by British soldiers in the Crimean War, and then by American and British soldiers during World War I, it became a popular nursery rhyme, its theme of decomposition as macabre as that of the bubonic plague in “Ring Around the Rosie.”

Today Carl Sandburg might be more well known for his poetry than as a musician, but his skill on guitar was likened to that of Andres Segovia, and his voice as “the voice of America singing.” Sandburg, who was known to respect poetry whether or not it rhymed or fell into free verse, once referred to modern poetry as “a series of ear wigglings.” Ear wigglings… or earworms?