A drug user high on a type of Spice known as 'Black Mamba' cut off his own nose.
Police described the scene, in which the man mutilated his face and other parts of his body, as a "blood bath".
Officers spent 30 minutes restraining the man, who was having an extreme psychotic episode, and carried him down three flights of stairs to an ambulance.
The man went on to recover in hospital and has since been receiving specialist support following the incident at his address in the Newtown area of Birmingham on October 12 last year.
The former legal high, which costs as little as £5 a gram, is described as being like "synthetic cannabis" - but some say it is more like heroin.
Its effects can leave users in a zombie-like state for hours where they appear frozen to the spot.
Other symptoms include psychotic episodes, hallucinations, seizures, vomiting and uncontrollable body movements.
Birmingham Police Superintendent Andy Parsons, said: "Some people are still viewing Black Mamba as a low-risk drug substitute and are taking it without any consideration for their safety.
"But our view is that there is no safe way to use Spice or Mamba.
"The reality is that these psychoactive substances can have catastrophic effects.
"Unscrupulous distributers are making it using dangerous, potent chemicals which can be lethal effect, while the psychological impact can be devastating and lead people to self-harm or harm others.
"We cannot stress enough that Black Mamba is a very dangerous drug.
"It is also now illegal to possess synthetic cannabis like Black Mamba and Spice so users could end up with criminal records."