At first, I wondered if this was a manga-exclusive chapter. But apparently, it was loosely adapted into episode 141 which was extremely late for such an early chapter. A lot of Studio Deen-era episodes were like that. I guess they really were struggling at the time.
Anyways, this chapter gave us a visualization of Ataru's character. Of course, it's really weird, which is to be expected from someone like Ataru.
Also, there was a female teacher in this chapter. Something we don't really see in the anime. Having a normal female teacher in that class is as good as suicide.