A Subtle and Clever Joke
Buttercup, Bubbles, and Rowdyruff, Blossom’s old enemies, are a threat, and they are set to meet in battle. This episode seems like it was made for the adults because the kids can barely understand the jokes.

Source: Reddit
Before the battle starts, the heroes realize that their muscles shrink whenever they are threatened. In the episode, you will see the boy’s masculinity shrinking. He then shouts at them because they did not defeat the girls, which makes the boys disappear.