It's based on the manga with the same name which is in the MU database. Sayonara Zetsubou Sensei which is about a depressed teacher with his eccentric students.

Anyways this is the Maria†Holic OP where my signature comes from. And no, Sayonara isn't Ecchi. The OP's experimental (!!!). Big difference. 😮

source: animenewsnetwork

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