a-sample
Explanation
The Joke
In the first panel, a man arrives at a hospital carrying something and says, "I'm here to drop off that stool sample you requested." This sets up a normal medical scenario -- doctors often request stool samples for diagnostic purposes.
In the lower panels, the scene shifts to the man at home with his family. His wife or partner asks, "Did they figure out why you're suddenly pooping bricks?" The man defensively shouts "NO" -- and a child chimes in, "They just laughed at me." The implication is that the man is literally producing brick-shaped or brick-like stool, and when he brought the sample to the hospital, the medical staff found it so bizarre or amusing that they laughed rather than providing a diagnosis.
The Humor
The comedy operates on the awkwardness and indignity of medical sample collection, amplified to an absurd extreme. The phrase "pooping bricks" is normally an idiom meaning to be extremely nervous or scared, but the comic takes it literally. The man is actually producing brick-like objects from his body, which is both medically alarming and visually absurd. The additional humiliation of the hospital staff laughing at his condition rather than helping him adds a layer of dark comedy about the vulnerability patients feel in medical settings. The child innocently reporting the laughter drives home just how degrading the experience was.