Sam is the dog of Chodey Dootch.
Sam usually got more food than Chode and a spot at the table, however on occaision, Sam would give chode table scraps. Dirty Steve eventually caught wind of this and swiftly put an end to it.
Sam acts as Chode's teacher and companion. When Chode got grumpy, Sam would always cheer him up, preventing suicide.
Unbeknownst to most people, Sam does not actually come from this world, but a far off moon. He arrived on this planet with the 1998 meteor showers in Arizona. He eventually walked to Canada where he found Chode sulking at a near by tire, where they first met.
Sam continues to help Chode, but secretly Sam was harvesting Chode's organs while he slept.