What the freakingheck is wrong with some people?

Police in Miami are investigating a brutal attack that led an armed officer to shoot dead a naked man who had bitten off the face of another naked man leaving him in critical condition.

The bizarre attack near the city's MacArthur Causeway on Saturday attracted the attention of passing drivers and several onlookers who alerted police and made attempts to halt the macabre spectacle, reports said.

"I told him to get off and the guy just kept eating the other guy," witness Larry Vega told the WSVN-Fox 7 station, describing it as something out of a horror movie with "blood all over the place."

Police then approached the attacker and told him to stop eating the man's face but he continued to bite into the victim, reportedly a homeless man.

"The guy just stood, his head up... with pieces of flesh in his mouth and growled," Vega said, and would not stop eating the victim's face.

A police officer fired shots that hit the man, but the attacker kept chewing on the victim's flesh -- more shots were fired, eventually killing him, the Miami Herald said.

Television footage showed the two men sprawled on the sidewalk side by side, with the victim barely conscious and covered in blood with up to 75 percent of his face ripped off.

Police said an overdose of a powerful new form of LSD could have prompted the attack.

"Whenever we see that a person has taken all of his clothes off and has become violent, it's indicative of this excited delirium that's caused by an overdose of drugs," Armando Aguilar of the Miami Fraternal Order of Police, told WSVN-Fox 7.

"What's happening is inside their body their organs are burning up alive."