The Hot Dog Monster first appeared in "Dad's Dungeon." It lays dormant with the Hamburger Monster as Finn's first trial in the episode. It seems possible that the hamburger and hot dog monsters could have been any number of other things, as Finn recalls that Jake had wanted hamburgers and he had wanted hot dogs earlier that same day. The Hot Dog Monster starts moving once Finn says "I don't think those burgers and hot dogs are burgers and hot dogs at all." Before it moves, some of the Hot Dog Monster's ketchup "charges up" and turns yellow, like mustard. After a brief fight Finn removes its brain, causing it to drool and roll on the ground non-aggressively. It is uncertain whether it dies due to its brainlessness, as Finn runs and knocks down the wall above the door to seal the monsters on the other side. The brain removal may be a joke referring to the Hot Dog Knights' being dumb.
The Hot Dog Monster's body is like a hot dog serpent with arms; it has a very large hot dog for its main body piece and a slightly smaller one for its head. The Hot Dog Monster's arms are made up of hot dogs slightly smaller than the one that is its head. The monster's neck is made up of a ring of hot dogs connected to each other width-wise forming a circle. It has a tail of hot dogs that taper in size as they get farther from his body. Each arm has three bunless hot dog fingers on the last arm segment. The hot dog monster's face has two bunless hot dogs pointing outwards as eyes, and two bunless hot dogs on their sides touching at the ends forming a mouth. The upper hot hot dog lip has mustard across it, making it look like a mustache. The hot dogs that compose the monsters body seem to have ketchup and mustard according to no particular pattern, though the only bunless hot dog with a condiment is the one with its mustache.