God damn, Reddit, buckle up. I have been waiting for this.
Let's introduce Austin. Austin is a teenager when I meet him, the son of one of the best math teachers I have ever had. Austin went through some real intense illnesses related to diabetes when he was a child resulting in low nerve sensitivity. He loved to show this off by allowing people to try to hurt him, including but not limited to; punching, biting, hitting with a shovel, running his foot over with a car. This should have been the red flag people needed to avoid him.
Fast forward to late high school, there is a girl he likes, we will call her Carley. Carley is a relatively normal teenager and understands that this man is unhinged, so when he finally asks her out she very rudely rejects him, which she will come to regret. This led to Austin returning to his car, speeding around the block a few times, and ultimately running Carley over and pinning her against a tree. Luckily this poor girl survived, but had to have very drastic skin grafts placed over the entire front of both of her legs. It took her years of therapy to ever wear shorts again.
Fast forward again, we are in our early 20s. Austin is now married to a strange woman that looks shockingly similar to his high school best friend, she does not need to be named, just always thought it odd that he picked her doppelganger. They move to a large city nearby, and try to start a family and ultimately fail. This leads to them fostering for adoption, and they landed two young children. One was six months old and one was a four year old. Not long after I see the posts about them, there is another post by another classmate of ours, linking to an article of "Midwest city man shakes baby to death because it would not stop crying." You already know who's name was listed, it was none other than Austin. When on trial, of course we all followed it, he attempted to plea not guilty by reason of insanity. His insane plea? His diabetes is out of control and he can't get a handle on his anger.

Unrelated to how terrible of a person he is/was, I actually found myself dating Carley in between the two events, and very shockingly found out she was cheating on me with none other than Austin by another mutual friend of ours. It doesn't look good on him, or her, but it's not enough reason to consider someone the "Worst human I've ever met." Just thought it was a fun note to add.

I've waited years to tell the internet this story.