the.com/crop circle

means A large, intricate pattern of flattened crops appearing in a field overnight, typically caused by people with planks, rope, and a lot of patience.

from The phenomenon took off in the English countryside in the late 20th century, with flattened wheat circles attributed by enthusiasts to UFOs, ball lightning, or other mysterious forces. In 1991, two English pranksters, Doug Bower and Dave Chorley, revealed they'd been making the circles for years using simple tools — a plank, a rope, and a baseball cap for sighting straight lines — deflating much of the mystery, though a dedicated community still insists some circles defy mundane explanation.