There's a voice line of Viper calling Omen Fred or something. I heard it once and never heard it again. What's his real name, and more importantly, what was that line?

I would normally get a max of 3 kills per game yesterday I got 5 for the first time with my killjoy alt I froze the last 2 people. But in the last kill I ran out of bullets so I had to knife him luckily he was still stunned