1x11 - Hell Teacher: Jigoku Sensei Nube

Tamamo, the fox demon Nube vanquished for trying to take Hiroshi's skull, reappears one day at Domori Elementary. When a furious Nube confronts him, Tamamo says he is no longer interested in Hiroshi and declares a temporary truce. However, he suddenly attacks the students of Class 5-3. It soon becomes apparent that Tamamo's true target is not the students, but Nube's special power.