Short Answer: Because it was horsing around too much! 🐴😝
Explanation: The pony got detention because it couldn't resist its mischievous nature and kept horsing around, probably galloping in the hallways or causing commotion in class. It just couldn't resist the temptation to have some playful fun! But alas, even our adorable pony friend needs to learn the importance of good behavior. So, detention it is! 📚🐾😄