Ep. 14: Koro-sensei's pool weakness exploited by Terasaka's failed assassination attempt
Aired on April 25, 2015

Koro-sensei fills Class 3-E with water, revealing his tentacles swell when soaked. Irritated by the class's harmony, Ryouma Terasaka allies with Shiro and Itona for an assassination. Terasaka triggers a transmitter that causes an explosion, endangering students and forcing Koro-sensei to absorb contaminated water to save them, leaving him vulnerable to Itona. Feeling guilty and tricked, Terasaka follows Karma's plan to infect Itona with a gas-covered shirt. Koro-sensei rescues the remaining students while the class uses the contaminated water to neutralize Itona's tentacles, forcing him and Shiro to retreat once more.
Episodes
- Ep. 10 · Irina competes against Lovro while the class visits Hawaii with Koro-sensei.
- Ep. 11 · Class 3-E prepares for a powerful new transfer student who claims to be Koro-sensei's brother.
- Ep. 12 · Class 3-E faces the baseball club in a high-stakes exhibition match against Sugino's former team.
- Ep. 13 · Karasuma faces a sadistic replacement PE teacher who challenges his student to a knife duel.
- Ep. 14 · Koro-sensei's pool weakness exploited by Terasaka's failed assassination attempt
- Ep. 15 · Koro-sensei offers tentacle shooting as prize for top exam scores in end-of-term finals
- Ep. 16 · Class 3-E and 3-A compete in exams, earning tentacles and an Okinawa resort wager.
- Ep. 17 · Hinano and Taiga prepare while Lovro trains students for the island assassination mission.
- Ep. 18 · Students face a virus threat while Koro-sensei remains trapped in an indestructible crystal sphere.