B.K. Slider (Real name Bill Keith Slider) is a Burger/Person from the Ybrik Series
He looks like a cheeseburger with arms and legs, he also has 2 eyes but no mouth, though he still talks somehow.
A reference was made to him in Super Ybrik where in Crystal Town there are two people looking at a poster, if you look closely you can see that it is B.K.'s concept art.
B.K. Slider is also confirmed to appear in Super Ybrik 2: Quest for the Stars as a singer/guitar player, the Player can pay 5 coins to listen to one of his songs.