Meant to put my answer:

The contraption is Martha's revenge.

I would like the Math Mom T-Shirt (XL)

Bob had two hobbies, bowling and showcasing his mint 1967 Gran Torino. Martha, Bob's wife, was tired of both. Bob decided to skip town on his aniversary to go to a bowling tournament. This was the final straw. On the night that Bob got back from the tournament, Martha got even. When Bob went to go to work the next morning, he found his lucky bowling ball welded in a jail of sorts. This bugged Bob a little, but he realized he could get it out. However, upon stepping outside he noticed his car completely stripped of its hood. Bob realized that the hood encased the bowling ball he saw. Bob never missed another aniversary.