- Roger the alien among us has always been somewhat amoral and sociopathic, but his behavior has been flanderized to an unsettling degree in later seasons. He may have finally crossed the line in the season 8 premiere. He becomes obsessed with Hayley, an obsession which culminates first in his shooting and injuring her then kidnapping her. He takes her to an abandoned warehouse, ties her arms & legs to the posts of an old bed and tells her he plans to skin her alive and wear the skin in order to "be closer" to her. After menacing the struggling Hayley by laying out the various tools he plans to use in front of her, Roger is interrupted by Hayley's husband, Jeff Fisher who finally gets him to listen to reason. Just when it looks like everything is going to be okay, Roger takes Jeff into the bathroom, skins him alive and comes out wearing his skin thinking it will make Hayley love him as much as she loves Jeff. The episode ends with Roger realizing he's no longer obsessed with the now-horrified Hayley and shows Jeff is still alive and will be getting his skin back, but it's still going to be difficult to erase such a terrifying episode. How would Jeff & Hayley be able to live under the same roof with him ever again?
- Roger may have crossed it earlier in "Virtual In-Stanity", where he kills five teenagers and brutally hits each with a limousine that he stole, simply because they didn't pay for their trip. What makes it more convincing that he crossed the MEH at this episode was that he neglected a bunch of puppies, destroyed an entire plane with people inside during his revenge streak, killed an innocent flight attendent by taking her parachute for the sake of having blood rush, and stating that has killed teenagers for not paying their fare to him the week before.
- Barry, when he is not medicated, crosses this in "With Friends Like Steve's". He takes advantage of Steve's family and earns the trust of Stan, then he frames Steve for destroying Stan's priceless collectors plates. When Steve is sent away to a correctional facility as a result, Barry then tries to kill Francine and Stan.
- Stevearino, Steve's Evil Knock Off is probably the most evil character in the series, to the point where the show doesn't even try to portray his actions as Crossing the Line Twice. His atrocities are not justified and are played very seriously, and include, but are not limited to, the following: Murdered and tortured multiple cats, tried to take over the original Steve's life by kidnapping and stuffing him in a small cage, planning to kill him later, and nearly killed both Stan and Francine when they finally figured out what was going on.
- One-time characters Nick and Cassandra, Francine's biological parents, either do this by abandoning her as a baby because babies can't ride first class, or when they wouldn't save Stan from being trapped under a wooden beam in his burning house because they didn't want to become a liability.
- Emperor Zing, another one time character has crossed this in the only episode he appears in. He humiliated numerous alien slaves in public by showing them memories of the rough patches they went through with their loved ones in public just for the sake of propaganda and deceiving the public while calling the whole ordeal a test and then removing the "tools for love" from such aliens who challenged his belief that love does not exist and he did that test on Jeff. He also forced the Majestic to only show the bad memories of the people who took the "test" and threatened to blow The Majestic into space if he disobeyed and showed the good memories. It is also implied that he tried to kill Roger by sending him to Earth to be a crash test dummy just because Roger cheated on Zing with another man, which could mean that Zing crossed the MEH long before his début.
- Stan crosses it when he tries to "unclone" a couple of cloned teenage girls that Steve created by killing them so he would not lose his job. He kills one such girl who tried to run away from him, which shocked Francine with Stan telling her not to judge him since she was just a clone. Stan later states in a later episode that he only kills for the sake of protecting others but when he killed that clone, he blatantly committed an act of murder.
- Stan may have crossed it in an earlier episode but fans have a hard time agreeing on when he crossed it. Such examples include framing Francine for a murder his boss committed just to prevent her from saying "I told you so" to him, kidnapping Greg and Terry's newborn baby out of homophobia and attempting to take her to Nebraska, and then there was this episode where he tries to get an atheist friend of his to become a Christian by intentionally making his life more difficult through getting him into a near death experience, brainwashing his wife into becoming a lesbian resulting in leaving him and taking away his kids, and ruining his business which causes that friend to attempt suicide and end up becoming a Satanist.
Moral Event Horizon / American Dad!