Three anecdotes come to mind for this topic:
#1
I once sent out a coding test email to a candidate.
Not long after I got an email back from this candidate saying "Hey bro could you do this test for me please." or words to that effect.
Obviously mistakenly forwarded it back to me instead of to his bro who he wanted to do his coding test.
#2
I definitely got catfished but it was by another recruiter who was fishing to try to find out who my client/employer was - he was hoping I'd call the number so he could pretend to be a valid candidate and I would reveal the name of the employer. I took the issue to the job board that the resume came from, and they threatened to ban his company from advertising on their board. Never happened again as far as I know.
#3
I've got about 150,000 resumes in my candidate database. One thing I'd be interested to do is run some sort of duplicate text detecter over my candidate database.
I've definitely received resumes that duplicate text from other resumes.