When I was 15 or so I get home from school and get a AIM message from an account I don't know claiming to be a girl at my school who has a crush on me, but too shy to reveal who she is. Which was weird all by itself because I didn't use AIM often.
At first I'm delighted, but she quickly becomes sexual. Talking about masturbating to me in very explicit detail. I get freaked out and stop responding. Which prompts an angry phone call from my Dad saying the account is messaging him now and bothering him at work. How she got my account info wss confusing, but i didn't even know my dad had an account.
So I respond a few more times, and very quickly "she" starts sending me porn, which then turns to sending CSAM saying I need to masturbate to it too. I'm freaking tf out and block the account. Which prompts another angry phone call. I tell my dad I don't know this person and tell him to just block the account to stop him getting bothered. He calls me a pussy and hangs up.
When he gets home, I tell him that the account was sending me freaky stuff. He stomps over to the computer, opens an terminal and typed a long string of characters that returns our IP address. "If it happens again, do this and we can catch this freak". He then abruptly closes the window before I can even read what he typed, much less remember it. He slams his bedroom door and that's the last I see of him for the night.
Took me a long time to fully understand and accept what happened that night, but I never looked at my dad the same again. There were a few more odd situations where he put CSAM in front of me or sent it to my step-dad getting him fired. But he died before I gathered the courage to confront him.