This happens on a number of occasions in Survival of the Fittest. After the deaths of his entire group, including the sickening deaths of Madelaine Shirohara and his love interest Amanda Jones at the hands of Cody Jensen Adam Dodd of V1 wanders across the island for some days in the throes of a Heroic BSOD - the whole matter getting worse as he gets attacked and is forced to kill classmates more than once.
A more minor example is with Sean O'Cann, who breaks down after his estranged best friend boyfriend and cousin are killed over the course of a couple of days.
Madelaine Shirohara goes into one of these as well after she is forced to kill her childhood friend Nanami Nishida following Nishida turning on her and her other friends.
Vatsy, from the dark-humor webstory Vatsy And Bruno, suffers one of these shortly after receiving the following rejection letter:
To whom it may concern: We do not regret to inform you that this submission is unusable, unintelligent and frequently illegible. We do not regret that your mental seepage, poured in such an ungainly fashion on your half-cent-per-thousand-sheet paper, will not be gracing this or any future publication of the Writer's Guild World Newsletter. We do not regret that you will - most probably - die alone, penniless, unloved and foul-smelling. We do, however, regret that we were exposed - even through this protective screen of incomprehensibility - to this most unspeakable body of work. We regret that our sanity and our lives can never be whole again after even a brief perusal of your first page. We regret that the stink of hideous purple prose and suspiciously fecal ink will forever saturate our desk space. Most of all, we regret that you had slithered, like a diseased rat infiltrating an unsuspecting granary, into this world on whatever dark day you were born (from the art inherent in your prose, we would estimate about a year ago.) If we ever see the name 'Vatsy' - or that name spelled differently, or any name with a superficial resemblance, or anything that even reminds us of you - on any volume, essay, poem, or bill that ever crosses our threshold, we will ensure that you will not survive the night that follows. Wishing you well, The Writer's Guild
Sapphire: When Boris kills Ivanka. He even tries to shoot himself, but backs down before pulling the trigger.
Shadow Of The Templar: Jeremy gets one after shooting and killing someone for the first time. It doesn't help that it was a head shot, meaning the guys brains exploded everywhere.
After DeceasedCrab finds the secret treasure at the end of his Let's Play of La-Mulana, he gets completely quiet for about three seconds before screaming, sobbing uncontrollably and starting to stutter sentence-like structures.
Our first encounter of Stuart/Amy in The Jade Box is of her in a BSOD from her Gender Bender.
In the Whateley Universe story "Ayla and the Great Shoulder Angel Conspiracy", Tennyo is attacked by ghosts from her past as The Star Stalker and she finally remembers. She remembers being a soulless, heartless monster capable of wiping out entire civilizations in her efforts to fight EldritchAbominations. She ends up nearly catatonic. For days.
In "The Cat In The Hat", the Critic spends an entire night out on a hill staring into space after a particularly scarring scene.
A calmer version happens after he angrily calls the director of My Pet Monster to complain, but then finding himself having to explain he's a 28 year old guy who watches little kid's movies for a living. This sends him into a depression on how pathetic this makes him until the end of the next episode.
Spoony has one of these himself when he reviews Highlander II and takes a moment to read the back of the VHS box and reads that it's the smartest cyberpunk movie since Blade Runner... He actually gets a pop-up error message (in this case a divide by zero error) and crashes.
He has yet another one at the end of his review of Night Claws. Upon witnessing Reb Brown get unceremoniously killed via Neck Snap, he can only stare in shock at the screen for about 30 seconds before silently stumbling away.
Linkara has one caused by his loss to Lord Vyce. A very legitimate, played straight BSOD as Lewis tries hopelessly to fix his old morpher, mumbling about losing and barely being able to beat Mechakara. It was quite sad.
He also had one after being told that he killed a little girl to create the magic gun. That girl was his daughter. However she wasn't and he didn't kill her but Dolorem told him he did.
He suffered a more literal BSOD after discovering that Ben Grimm's Character Development in Spider-Man and the Fantastic Four in: Brain Drain was penned by Marvel's former editor-in-chief.
In Red vs. Blue, the Reds eventually discover the true purpose of their battles: They're basically labrats and are set up in situations to train the Freelancer and see how the Freelancer would act in that situation. They also discover that the Reds and Blues were intentionally chosen to be idiots to make things easier for the Freelancers. After Sarge realizes what this means, he winds up hastily constructing a Red Base out of scrap parts, deciding that if he's trash, he should be a sergeant of trash. He also relinquishes his rank as leader of his trio.
Super Mario Bros. Z heavily implies that Shadow's current Jerk Ass nature was the direct result of the immense trauma of having to witness the two only friends he ever had (or at least the two only people he could openly refer to as friends), Rouge and Omega's, deaths at the hands of Mecha Sonic during his decimation of Mobius.
Life In A Game star Guy goes in to a particularly epic one after Subplott is killed by the player controlled Jackal. He gets better.
In the backstory to Funny Business, after Jeannette grows old enough to understand that she hurt people by abusing her powers, she essentially loses the ability to ever be happy again. Of course, her parents noticed her sudden change in behavior but did not know of its cause, and once they started to worry about her mental health, she inflicted them with Laser-Guided Amnesia and pretends to be a Cheerful Child from then on, so that nobody would worry about her. She keeps the Masquerade up right up to the present time of the story.