Nintama Rantarou: 100% Yuuki! Dokutake Dejiro wo Yattsukero no Dan
Rantaro, Kirimaru, and Shinbee are taking a stroll and come across a beautiful field, and the students of the ninja academy then decide to take a field trip there. However, the field is actually full of poisonous mushroom traps.
[Source: Anime News Network]