A rapper is tying up police emergency lines by bombarding a force with nuisance calls.
He dials 999 before rapping to operators at Greater Manchester Police - who are not allowed to cut him off.
Despite officers blocking more than 60 SIM cards, the man has plagued them since January 2009.
Police said the man "has made thousands of calls where he chants, sings, raps, preaches and plays loud music to call handlers".
In the past three months he has made 700 calls, lasting between three and five minutes, slowing down the call handlers' response to other calls.
However, a police spokesman said there was never an occasion when a call was missed. The caller would have to put the phone down - the system would not let it ring out.
Supt Karan Lee said the caller's "inappropriate outbursts" are putting "lives at risk".
During many of the calls, the operator answers the phone to be met with a barrage of music and rants.
His rapping is difficult to decipher but during one call he started shouting about his citizen's rights.
So far officers have managed to establish that most of the calls are made from the Moss Side and Trafford areas.
The call handlers are tied up for several minutes trying to deal with him because they have a "duty of care" to the caller - just in case there is a real emergency situation.
Call handling manager Jason Unsworth added: "You can never guess when this man is going to call up, and that's part of the problem.
"With the World Cup on at the moment, it's an added pressure when he does call, because it can be any time of the day, and he can be on the phone for several minutes.
"He is causing us a big problem because of the sheer volume of calls he makes and the time wasted dealing with him.
"We have to treat each call as if it was a real emergency, so it's frustrating and worrying when we get time wasters preventing people with real emergencies coming through."
Clips of some of this man's nuisance calls have been released and police are urging anyone who recognises his voice, or who has information about who is responsible, to come forward.
Supt Lee added: "Nuisance calls are no laughing matter.
"I do not know what motivates this man has to keep calling but we need to stop this man's time-wasting calls before someone's life is put in jeopardy."