My colleague tried to get me fired after just two weeks into the job! Apparently, he started a diary on my very first day of things he didn't like about me and the minor mistakes I made, even though I had only just started. He also used the threat-protection software installed throughout the company to spy on everything I was doing, which breaks GDPR laws.
HR never presented me with his list of complaints, making it hard to counter with my version of events. And excuses were made as to why I was being spied upon, probably to avoid having to fire him and dodge possibly legal action. I quit weeks later after too much stress and sleepless nights.