Yep. I was actually at the center of mine.
From grade school onwards, I was in the same classes as a guy named Matt whose dad worked at our high school. Matt was a whiny douche who couldn't stand that I didn't like him. From sixth grade onward, we had a bit of a feud going on. It started in Music class when I told Matt his fingernails were too long to play guitar correctly (They were, the music teacher said the same thing five minutes after I did.) To Matt's mind, that constituted bullying.
For the next several years, I'd get two or three parent-teacher conferences a semester, instigated by Matt's complaints, that never really went anywhere. God's honest truth, I didn't want anything to do with him. Never bullied him in the slightest. Even looking at Matt was enough to earn me another brush with the administration and starting shit was just more trouble that it was worth. I didn't even hate the guy, dealing with him was just such a chore that I avoided him whenever possible.
Fast forward to Sophomore year of high-school. Our rivalry has been flared up by a small group of guys hoping to watch a fight and the assistant principal hears about it. Hoping to cut it short, Mr. Jones calls us all into his office for explanations. On the official record, only one kid named Nick is willing to say anything. He says he heard Matt say he was going to "shove [my] dad's dildo up [my] ass sideways." Since I've been doing my best to stay out of shit with Matt, he's on the hook.
Then a knock comes at the office door. Matt's dad is there. He's hoping to throw his weight around and get me suspended or expelled. Mr. Jones takes him out in the hallway and you can hear this guy screaming about how I've been bullying his son since grade-school and no one will do a damned thing about it.
Mr. Jones, bad-ass mother-fucker that he is, tells Matt's dad to quit his bullshit. Matt's been starting the trouble all along, based on the evidence. Dead silence in the hallway.
Mr. Jones comes back in and, after dealing with Matt's crazy dad, decides no one needs to be punished as long as it ends immediately. I agree, Matt agrees, and we all go back to class.
Next day, Matt and his dad aren't at school. Since his dad was such a popular teacher among the redneck students, people start asking questions. Eventually, it trickles out that Matt is in the hospital, along with his mom and two younger brothers, and his dad is in jail.
Apparently, Matt's dad had been abusing the entire family for years and his "humiliation" with the assistant principal finally made him snap. Matt's injuries were life-threatening and the family's only slightly less serious. They'd all intervened trying to keep dad from killing Matt.
Matt didn't come back to school after that. His mom divorced his dad, got a restraining order and moved the whole family half-way across the country to live with her mom. Dad did maybe a year in jail and lost his ability to be a teacher, which wasn't really a hardship since he taught shop and could still make decent money as a tradesman.
Still makes me feel kind of weird and guilty when I remember it. I know I did everything I could to steer clear of Matt, but he still almost died because we didn't like each other.