There's a couple I can think of, but they weren't partners.
One was a guy who messaged me on OKC. He got shut down super quick because he wasted no time in saying he had a diaper fetish and he asked me if I wanted to be his mommy. I laughed at him and asked if he was for real. He was serious. So I laughed some more and denied him. I wish I remembered what I responded with, but I know I blocked him shortly after.
The other guy I also met from OKC. He was actually pretty interesting and cute and we were into each other. Despite him living around 5 hours away, he was determined to see me, so I was all "Alright, let's make plans, then".
We actually ended up meeting a couple times but we never reached a 3rd time. I'll get to that point in a second, but this guy seemed a little too desperate, despite how he ghosted on me for a good while. He then would tell me he wanted to see me again, and got too weird... I tried explaining to him that I'm not in a position to just come over and see him, and I said "Maybe when I'm on fall break".
However, he would go through periods of not contacting me, and when he would contact me, it was literally only stuff like "I miss you, I wanna fuck you again." The last time he texted me though, he said I should come over and see him because he's going to celebrate a friend's bachelor party and that "he's always wanted to be in a threesome. Want to join him?" and I was so revolted at the thought. The dude barely knew me and he's got the gall to ask that?
I didn't freak out on him, but I told him calmly I wasn't into that at all and I was really upset over it. He's not contacted me since and I deleted him from my phone.