Ojay Miller, better known as Mayhem and Mayhem NODB (commonly stylised as MaYHeM NODB), is a grime MC from Birmingham, England. He is one of the founding members of NODB alongside Deadly.

Mayhem started rapping in primary school and by the time he was 14 he was performing at dances and raves. He rose to prominence in Birmingham with the song Pum Pum Punashum.

NODB was the first grime group from Birmingham to feature on BBC 1Xtrathis helped to popularise grime in Birmingham and the wider West Midlands. In 2011 Mayhem was released from Prison and he created and released his first CD  Mr Splash in 2012 when Mr Splash was released Mayhem was confused and angry after just being released from Prison, it features a gritty sound. Mayhem's second album was titled  Its Peakum which was released in 2013 and features a more accessible sound when compared to Mr Splash and in 2015 the mixtape "Gassum" was released which features London MC Big Narstie and Deadly.

In 2012 Wiley released Step 2 Freestyle in which Mayhem alleged that Wiley copied his style by using UM at the ends of words something which Mayhem has been known for. Mayhem was angered by Wiley stating that he did not know who he was, however, Mayhem claims they performed at various raves together. Wiley then followed up with his track Step 6 and at 1.22 of the track he reaffirms that he did not know who Mayhem was. Mayhem responded with a video titled Mayhem NODB Replies to the Cat Wiley.