Chef Bork Bork is a foe in The Horrible Hunger of the Ravenous Wattle Gobbler
This is a Nomad Pyro that you are dealing with. Avoid using fire on him but everything else is fair game. He will lob grenades and use his flamethrower.
Headshots and kneecapping
The name "Bork Bork" comes from the Muppet's Swedish Chef.