Shevok'tah gish

Shevok'tah gish was a piece of Klingon opera.

Pek'tu-Keltz once sang the complete cycle of Shevok'tah gish for M'Rek, without stopping to eat or rest. 

When Ezri Dax rescued Worf from the escape pod from the he had been stranded in, Dax guessed he had been singing opera like Shevok'tah gish. Worf had been singing opera, but Gav'ot toH'va.