- Avalon has Alison grow noticeably more full of herself and frustrated at the antics of her friends as the years progressed.
- Bittersweet Candy Bowl sees Mike go from a Nice Guy to a bitter Jerkass as part of its Deconstruction of the Tsundere archetype. Turns out all those years of getting punched around while his friends laughed have taken their toll. To make matters worse, by the time he finally snaps, Lucy has actually improved, and his newfound nastiness and need to vent all that pent-up frustration leave her more of a mess.
- Joni from Boy Meets Boy is shown as a good, somewhat tomboyish straight girl and friend of gay teens Paul and Tony. But then she hooks up with dumb jock Chuck, who is really most likely dating her out of spite for a previous girl who spurned his advances, and things go downhill from there. Although her friends try to like Chuck, it's no good and then they don't try very hard to hide how much he annoys them. Even so, this doesn't excuse Joni for giving all of them (except Chuck) the silent treatment, not returning calls, or dropping completely out of their lives after about a decade of friendship. To her credit, she probably goes back to making nice with Paul and Tony in the end.
- In Commander Kitty, Nin Wah chooses the absolute worst time to sabotage CK CK for her own benefit. She spends the next page apologizing, but it doesn't change the fact that 1. CK was in the right for once (surprisingly) and 2. the entire rescue operation would be over already if she hadn't caused Zenith to blow a fuse.
- Due to sleep deprivation, Jade Harley of Homestuck has gotten a lot grumpier - although it should be noted that she's only like that to the trolls, who have been picking on her for her entire life (with the exception of Tavros). She got better later on, though.
- Something similar happened to John in Act 6 due to Cabin Fever.
- According to Aranea, Cronus wasn't always as big a Jerkass as he later became, but he was never exactly a nice guy, either. Apparently, the revelation that magic didn't exist - something he'd based a good deal of his life around - caused a Heroic BSoD leading to this trope.
- And now, Aranea herself combines this with FaceHeel Turn, becoming not only more sadistic and arrogant, but also unbelievably smug.
- Ménage à 3:
- DiDi originally appeared to be sweetly nice if ditzy, but her desperate desire for an orgasm eventually drove her to increasingly erratic and sometimes bitchy behaviour. Some readers, looking at her earlier casual, careless treatment of her numerous boyfriends (and her later insanely unthinking treatment of the frustrated Zii), suspect she was a bit of a Bitch in Sheep's Clothing all along, but it might be more accurate to say that her ditziness is actually nigh-autistic social and emotional incompetence.
- Sonya also initially came across as The Ditz and none too bright, and rather the victim of Ziis Casanova tendencies. However, she soon discovered a quite dangerous love of Drama and even danger and demonstrated increasing levels of low cunning, and while her Stalker with a Crush behavior could be seen as Ziis follies coming home to roost, Sonya proved quite willing to use anyone to get her way.
- Tracy initially looked like lead character Garys born geeky soulmate. However, she then started coming across as ridiculously pushy and sexually manipulative, bouncing Gary into sexual activities that he never really wanted and that looked borderline nonconsensual. It's telling that even Extreme Doormat Gary eventually got fed up and washed his hands of her. However, its questionable whether this was Character Development or whether she was probably like that all along.
- Seymore of Sinfest became more and more of an asshole around 2010, culminating with the "Bad Behavior" series.
- Sandra big time during her FaceHeel Turn. It takes a while before she reverts back to a nicer persona.
- Wally, post-timeskip, acts a lot more insensitive towards his friends (see Innocently Insensitive), and has no qualms about saying he is willing to destroy Sandra in front of her former friends. Said friends include his current girlfriend, Crystal, who he knows was Sandra's closest friend.
Took A Level In Jerkass / Webcomics