Car Owner Asks What Caused Strange Crosshatched Blue Marks on Bumper and Fender, Reddit Points to Culprit Who Hit Twice

A post in r/whatisit shows a black vehicle with light blue crosshatched marks on its front bumper and fender. The original poster wrote that they noticed the marks without having hit anything, and asked commenters for theories on what might have caused them.

The photos show two separate patches of the crisscrossing pattern, one on the lower bumper panel near the wheel well and another higher up near the headlight assembly. The marks appear as a light blue or teal residue layered in diagonal lines running in two opposing directions.

Several replies pointed to a collision as the likely cause. One commenter wrote, "If I had a guess, someone bumped you then backed up hence why [sic] it's cross hatched, looks like a plastic type material. I bet if you took a fingernail to it you'd be able to peel off bits of it."

Another offered a detailed explanation of how the bumper's flexibility could be the reason for the pattern seen in the photos. They wrote, "Near the top of the scratches the bumper did not flex, and so the scratches in both directions are roughly parallel with the ground. Lower on the bumper there's no support behind the plastic, so the bumper flexed inward during the impact."

The commenter added, "The line from the initial point of impact would then move upward as the plastic bent in underneath the support above it. Then as the offending car reversed, the same thing would happen, resulting in this crosshatching. It's more pronounced the more the bumper flexed, hence why [sic] the lines are parallel at the top."

Others suggested the marks came from a rolling wheel rather than a direct vehicle-on-vehicle collision. One person wrote, "It was done by some sort of rolling wheel. The downward strokes are from the approach and the upward strokes were as it passed by. The height of the top marks suggest the wheel was significantly shorter than a tire and had abrasive protrusions distributed but [at] not uniform [sic] intervals."

Another raised the possibility of an automatic car wash as the source. They wrote, "My thinking is an automatic car wash, but I don't know how you don't notice immediately afterward."

One commenter theorized the car was hit twice. They wrote, "They hit you twice, forward made the lines go one direction, then they backed up and scraped against you again, which is why it's hatched."

This article is based on a post shared in r/whatisit on Reddit. The Daily Dot could not independently verify the cause of the marks shown in the photos, the identity of the original poster, or the vehicle's ownership history.