Nightmare is the fifth studio album by heavy metal band Avenged Sevenfold, originally released in 2010. It was produced by Mike Elizondo and mixed in New York City by noted engineer Andy Wallace. Nightmare is the first Avenged Sevenfold record without James The Rev Sullivan performing drums on all the songs due to his death in December 2009; however he did write parts that were used for the final recordings, making this the last album he would write on - The Rev's vocals are still on the album as a tribute to him.
This is the only album to feature ex-Dream Theater drummer Mike Portnoy, who performed as the drummer for the album in his place, also played with the band for all their tours through the end of 2010, due to his separation with Dream Theater. The album has been certified Gold by the RIAA in the United States. The album debuted at #1 in the Billboard 200.