Within the industry, "botch" is often used for when someone screws up during a match. This can mean anything from a wrestler falling down before their opponent's move connects, or missing a cue, or lacking the strength/dexterity/technique to complete a maneuver. Often it just looks foolish and is generally harmless, but less fortunate occasions have led to serious injury and even death.
Many a wrestler has been unintentionally caught on camera "blading," which is when a wrestler secretly (when it goes right, anyways) nicks their forehead with a razor blade to create the illusion that they've been cut by one of their opponent's attacks. Usually this happens thanks to the camera being on them at the wrong time. "Caught red-handed" indeed.
It's not uncommon for the audience to be able to occasionally overhear wrestlers giving instructions to their opponent so they can get ready to act out the next move, as Botchamania's "Everyone Talks Too Much" gag demonstrates.
During the WWE Summerslam 1997 match between Mankind and Hunter Hearst Helmsley, Mankind, at one point after getting beaten down, suddenly ripped his shirt off, then had a My Name Is Inigo Montoya comeback, leaving fans wondering what was going on. Mick Foley (aka Mankind) later shed some light on the subject in his autobiography: turns out, there was supposed to be a heart-shaped tattoo on his chest, symbolizing his transformation into his former fantasy persona from his high school/college days, Dude Love (who fans had been introduced to through a series of Worked Shoot interviews in the weeks before the match). Unfortunately, Mick forgot to get the tattoo done, and didn't realize it until he was due to make his entrance for his match. Thinking quickly, he scrawled the heart on his chest with a magic marker; unfortunately, by the time of The Reveal, it had sweated off. Oops.
And then there's the big unmasking of Kane at the hands of Triple H. Kane's backstory had him as a childhood burn victim, so naturally, this was a big deal. Unfortunately, the burn makeup under the mask completely failed to hold up through the match, so when Kane did unmask, he didn't look like a victim of a horrible house fire so much as a victim of an attack by a psychotic Mary Kay lady and a deranged barber with a thing for Larry Fine. Thankfully, rather than press on with the storyline, the next week, Kane appeared without makeup, but still claiming to be terribly burned, thus making the false scarring yet another dimension of his uniquely psychotic delusions.
There have been some theories as to why Kane's make-up job was so horrific. The most popular one was the heavy black eyeliner Kane wore under his mask started to run. Thus when he unmasked, his face was covered in black make-up splotches. It also did not help that when he removed his mask, it was revealed that Kane was completely bald on the top of his head save for the hair on his sides. The long locks he sported for years were actually part of the mask itself and he grew out what hair he had left. WWE quickly reacted to this; having Kane lose the make-up, shave himself completely bald and have him wear a towel over his head for a few weeks afterwards before making another reveal.
Well, they tried to continue it. For a while when they showed video of the unmasking they slowed the tape down, added a silly sound effect that was supposed to be ominous or something, and used a cheesy effect to distort his face. To point out how bad it was, when something is simply too cheesy for Vince McMahon...
Shockmaster's mask, a purple-silver spray-painted Star Wars Storm Trooper one, falls off, revealing the bald head of Fred Ottman, AKA "Tugboat".
Everyone present starts cracking up (clearly dropping a couple f-bombs on live television), including the announcers.
Ole Anderson, providing the voice of the Shockmaster, desperately tries to salvage the segment and fails, due to the voice modulator sounding like a cardboard tube. (Bonus points: after the fall, you can clearly hear Ole, having forgotten to mute his mic, laughing and muttering, "Oh god.")
What makes it worse is that the only part of this that could have been salvaged was the "trip and fall" part. Ottman had actually had a few practice-runs and everything had gone fine, but when it came time to do it live, an extra cross-beam was added he didn't see until he was already mid-jump. If things had gone off without a hitch, it would have been a really bad-ass entrance. The costume and voice, however, still would have been atrocious.
During one WWE PPV, The Undertaker's entrance made it appear as if he was floating down to the ring. This would've looked cool, except the cameras filming the entranceway were angled completely wrong and revealed the board he was standing on.
During CM Punk and Chris Jericho's 2012 feud, Jericho would assault Punk with bottles of alcohol. On at least one occasion, he squeezed a sugar glass-made whiskey bottle while swinging it at Punk's head, causing it to explode in his hand.
During Hulk Hogan's infamous WCW match with The Ultimate Warrior, Hogan was supposed to blind the Warrior with some flash paper. Unfortunately, it went off in Hogan's hand, burning him instead.
Whilst making his entrance at the Elimination Chamber 2010 PPV, The Undertaker stood on the rampway as the flames beside him onstage went off. What Taker didn't expect was for one to go off right underneath him, and he was very briefly engulfed in flames. If it weren't for the heavy leather coat he typically wears to the ring, Taker would have suffered serious burns all over his body. Calaway reportedly went ballistic about it backstage after the match had ended.
A separate and much more serious incident occurred on a January 2008 episode of SmackDown. Jeff Hardy was making his entrance for an interview segment when the stage pyro went off with too much force and sent sparks into his eyesnote According to statements made, the pyro used was a so-called "cold pyro" that was designed to not cause burns, similar to what Goldberg used for his iconic entrances. But in this case, the sparks went straight into Hardy's face and eyes, places where microscopic bits of incendiary powder and metal were not meant to go.. He fell to the ground in pain and rolled right onto the section of grating where flame pyro erupted from beneath just seconds later. The segment was cut short, Hardy was hustled onto a stretcher, and even his on-screen opponentEdge hustled up the ramp to show concern. However, this was very likely a Worked Shoot.
In Shoot Wrestling, which aims to be the legit competition counterpart to "show wrestling", anything blatantly illegal that would never be allowed in a real sport qualifies. A most infamous instance being Akira Maeda sending his leg into Satoru Sayama's groin during a Universal Wrestling Federation "bout" but even as the shoot feds developed into full on mixed martial arts promotions, favored wrestlers like Bob Sapp were notorious for getting away with groin attacks, making the referees look incompetent and giving the fights in general a bush league atmosphere.(compare to, say, the controversy caused by discrete greasing at UFC 94)
TNA uses disguised Cardboard Boxes to protect wrestlers during more dangerous matches. During the 2007 Slammiversary a some not obscured boxes were visible Abyss and Tomko's match though.