Reddit users may have helped another man solve a medical mystery that might have saved his life. A Reddit user submitted a web comic known as a rage comic detailing his male friend’s experience of trying his ex-girlfriend’s unused pregnancy test as a joke.

He was shocked when the result came back positive. While the user intended the story to be amusing, others pointed out that the false positive test could be a sign of testicular cancer.

He got tested and it turned out that his friend had a small tumor in one of his testicles. Because it was found so early, the cancer could be treated immediately.