David firting with Crystal. Seems harmless enough, untill you consider that Crystal had just lost her only remaining family member and that David was only doing it to amuse himself, rather than being genuinely interested in her... dick move, mate. Dick. Move.
What got Discord killed on Cerberus Daily News - the idiot thought it'd be a *really* good idea to advertise a slave auction on the public-access Extranet just to rile up people. Unfortunately for Discord, most of the people he was taunting happened to be mercenaries who happen to look down on the slave trade. The resulting Extranet Counterattack led to forum members hiring a squad of mercenaries to murder Discord and free the slaves in his possession.
Cody Jenson: Raped Madeline Shiohara and bit out her neck. How did he feel? He didn't.
Danya: Establishing Character Moment in the first version was when he was briefing the v1 students with a very... smug tone. Then towards the end mentioned he hated punks, and ordered his minions to kill a student for wearing his hat sideways.
Jeremy Franco kicking Kimberly Nguyen in her bullet wound for refusing to give him her fedora, then taking it anyway.
In the video The Unspeakable Deeds of Bill 42, it's not enough for the character representing the bill to fine people for meeting to air their grievances. He has to up the evil quotient by deliberately knocking over a woman's crutches.
The Ascended Meme NEDM (Not Even Doom Music) came from a literal example of this. Except, replace "kick" with "burn," and "dog" with "cat." Anonymous was not pleased.
Awkward. has a fight between Lester and Alex culminate in Alex telling Lester to give up on his relationship with Steph because "everybody knows you're just going to mess it up like last time". Lester doesn't take it well. Later we find out that Ernie dumped Karen, calling her "worthless".
Something Awful's Awful Movie Database has "The Terrible Truth About Dolphins," allegedly a "documentary" but mostly concerned with the director's overwhelming hatred for dolphins, who are abused throughout the movie.
Welcome to Night Vale gets this with Strex giving Cecil a birthday present. It attacks Khoshekh and leaves him hospitalized. Strex didn't understand why it didn't work out.
General Ryde in Engines of Creation kills one of his own men by crushing his skull with his boot for being so stupid as to get injured.
In the webseries and novel versions of Noob, one of Roxana's earliest story-relevant moves was to kill Sparadrap's entire pet collection.
Mannequin and Burnscar getting revenge on Skitter by attacking her territory and brutally killing dozens of civilians, with Mannequin making a point to murder parents in front of their kids.
Attacking Parian's territory and killing nearly everyone there, including Parian's family, before mutilating the survivors to look like them so that they can serve as decoys to draw the fire of local Neo-Nazis. To top it off, one of the Nine members the victims were altered to look like was the Siberian, who literally cannot be harmed by anything, so the motivation was sadism as much as tactics.
Attacking a hospital and starting with the nursery. It also bears mentioning that the hospital was in a rural area and served multiple counties, so it was both very crowded and too far for anyone but the police to intervene, and it's implied that the Nine picked this target specifically to ensure that the chances of escape or rescue were virtually zero.
Attacking a ski resort and gruesomely killing nearly three hundred of its residents before kidnapping 999 more and stashing them away, promising to kill them if anyone but Theo tries to stop them.
Bonesaw kidnapping Blasto, using him to clone the Nine, and then forcing him to sing a children's song for four solid months before he drops dead from a stress-induced stroke.