When jaws drop, eyes are covered in disgust or parents are outraged, shock rock has done its job.

Based on theatrics, wild costumes and/or lascivious behaviour, there are minimal rules to shock rock: look crazy and act crazier. Even the music itself has few regulations; generally tied to heavy metal and punk rock — genres as extreme and reactionary as their esthetics — it doesn't matter as long as it pushes boundaries.

However, while many try (for example: Marilyn Manson and Polish black metallers Behemoth burning Bibles in an attempt to outrage), intentionally or unwittingly, few artists are inherently shocking. Of those, some have even taken shock rock to insane levels, resulting in careers so outrageous that one particular moment fails to fully convey their excess. From the inadvertent to the blatant, here are a few great moments in shock rock.

• GG Allin: This one's simple: defecating/urinating onstage and throwing it at audience members, beating himself bloody with microphones and engaging in fist fights and rampant drug use were all standard fare at Allin (who died from an overdose in 1991, yet remains unequalled) shows. 'Nuff said.

• The Plasmatics: Taking a more artistic stance, New York punks The Plasmatics dumbfounded the world as they blew up equipment, chainsawed guitars, performed on the verge of nudity and — as a tour opener — drove a Cadillac loaded with explosives towards a stage full of musical equipment, jumping out seconds before impact.

• Mayhem: Gross and maybe a bit stupid, Norwegian black metal stalwarts Mayhem have been involved in everything from church arson to murder. Two standout moments: guitarist Euronymous, upon finding his singer dead from a self-inflicted gunshot wound to the head, before calling authorities, took a few snapshots (using one as an album cover) and allegedly nicked pieces of brain to make a stew. Years later, as the band was attacking a dead sheep's head live, the head flew off the stage and struck an audience member, fracturing his skull. After surgery, the band offered the wounded fan... a free concert ticket.

YOU HAD TO BE THERE

Sometimes though, the best moments are when tables turn, most notably on genre luminaries. They end up caught in situations that establish them as shock rock royalty but upon further inspection, it would seem as though they were just in the wrong place at the right time. Witness:

• Killer chicken “Coop”: Possibly the earliest recorded moment of true shock rock comes from universally acclaimed genre king Alice Cooper. Revered for pioneering the movement via a stage show featuring guillotines, live snakes and bloody props, it was his performance at the 1969 Toronto Rock 'N' Roll Revival concert that solidified his role as Gore-Rock Grandaddy. When an audience member threw a live chicken onstage, Cooper — admittedly knowing little about the birds — thought if he tossed it up, it would fly away. Sadly, the fowl flapped but did not become airborne. Landing in the crowd, it was torn apart while still alive, spewing carnage, prompting headlines about a chicken-killing crooner and inciting Humane Society visits to his shows for years.

• Bat boy: Another, almost identical “stuff of legends” incident came from self-proclaimed Prince Of Darkness Ozzy Osbourne during a January 1982 concert in Des Moines, Iowa. While the tale has been distorted over the years, in essence, another weird fan tossed a critter onstage. This time? A bat. Instead of throwing it back though, The Ozzman stuck its head in his mouth. As related to press many moons later, he “...thought it was a toy. It must have been stunned by the lights because it looked dead when I picked it up. I put it in my mouth as a joke. Its wings started flapping and I ripped it out of my mouth but its head came off!” Multiple painful rabies shots and countless sensationalized news reports later, Ozzy's shocking status was sealed, yet he now refrains from gnawing on fan-based gifts.

• Involuntary organ donation: Richmond, Virginia's Gwar is inimitable. Slaying creatures onstage in full monster garb and spraying the audience with the carnage, they pride themselves on one of the wettest, most politically incorrect productions in music history. Therefore it was of great surprise when in 1992, lead singer Dave “Oderus Urugnus” Brockie was the outraged one after he was arrested and his costume's prosthetic penis was confiscated by the Charlotte, North Carolina police as evidence of his indecent exposure and lewd conduct. Temporarily banned from the state, Gwar eventually turned the incident into the album America Must Be Destroyed, which the band eventually did... even if “America” was just a set of cardboard cutouts.