A double dactyl is a biographically inspired humorous poem with very strict structural rules. Here are links to two definitions for those who are curious. The first from the Poetry Foundation is clearer but less accurate than the second, from Wikipedia. Take your pick. The classic statement is the book Jiggery-Pokery: A Compendium of Double Dactyls by Anthony Hecht and John Hollander (New York, 1967).
Dactyls in Wonderland
Snicker-snack, snicker-snack
David Del Tredici,
Losing his taste for the
Serial style,
Started composing more
Neo-Romantically,
As he obsessed about
Alice awhile.
