What is a headscratcher? It's a story that may leave you with even more questions or prompt you to ask, "What were they thinking?!"
Here are some of our most memorable headscratchers from San Diego in 2017.
Ghost Ship in Plain Sight
There were more questions than answers after a 120-foot shipping vessel burned for days beginning Sept. 29.
The smoke was visible for miles when the ship was engulfed in flames near Seaport Village.
The problem was, no one seemed to know who owned the vessel.
Days after the fire broke out, Port of San Diego officials said they only had the name of a shipping agent in Barrio Logan. That man said even he didn't know the owner.
The Norton Sound had been docked in San Diego Bay for eight months.
Not-So Advanced Placement
The College Board invalidated 844 AP exam scores after a test proctor filed an incident report that one student was suspected of cheating at the school.
In July, the San Diego Unified School District voted to take legal action however a federal judge later ruled that the students would have to retake their exams and their tests remained voided.
About 200 students opted not to retake some or all of their AP tests after the debacle, and the families were promised refunds.
In the end, a few families told NBC 7 they only received a partial refund for the canceled exams.
In March, it was tough to find glue in San Diego. A craft craze called “slime” caused a shortage of Elmer’s Glue at stores nationwide, including some in San Diego.
“Slime” was so popular at one point, that kids were sharing or even selling creations online and parents were bemoaning how difficult it was to find supplies.
Someone used a stolen piece of construction equipment to tear a bank ATM away from the building but failed to steal the machine, San Diego police said.
A trail of debris was left on Oct. 30 at the Union Bank on Waring Road in the Allied Gardens neighborhood.
Police found several packages of cookies and a golden mask on the floor of the wheel loader.
So far, no one has been arrested for the bizarre crime.
A cat reported missing in California in 2014 showed up in Canada nearly three years later looking well.
BooBoo the cat was reported as missing in August 2014 in Watsonville, California.
Then, she showed up in Ontario, Canada in "fantastic shape." It was suggested BooBoo may want to consider a diet when she gets home.
Onesie With Special Sauce?
McDonald's rolled out some new merchandise in July including the Big Mac onesie for adults.
There were also french fry-themed sweatsuits and hamburger pillowcases.
Not to be undone, KFC also offered its own collection of clothing and jewelry.
Destined for our 2017 Year-in-Review headscratcher list.