Carlson is a laborer on the ranch where the main characters George and Lennie go to work in John Steinbeck's novel Of Mice and Men. When the reader first meets Carlson in chapter two the setting is the bunkhouse and Carlson asks Slim about his puppies. Slim is the mule skinner and a leader for the men. His dog, Lulu, has just had a litter of puppies.
Carlson wants Slim to give one of his puppies to Candy, the old swamper. Carlson claims that Candy's dog should be euthanized because it is old and smells bad. Carlson says,
“Well, looka here, Slim. I been thinkin’. That dog of Candy’s is so God damn old he can’t hardly walk. Stinks like hell, too. Ever’ time he comes into the bunk house I can smell him for two, three days. Why’n’t you get Candy to shoot his old dog and give him one of the pups to raise up? I can smell that dog a mile away. Got no teeth, damn near blind, can’t eat. Candy feeds him milk. He can’t chew nothing else.”
Later in chapter three Slim agrees that Candy's dog should be put down and offers Candy a puppy. The old man is distraught and doesn't respond to the offer. Carlson uses his Luger to shoot the old dog. The purpose of the scene is to provide foreshadowing for George's eventual shooting of Lennie in chapter six. At one point Candy told George he should have shot his own dog. This leads George to the idea that he should be the one to kill Lennie after the accidental death of Curley's wife.