R.O.B. (short forRobotic Operating Buddy) andProfessor Hector are guest characters that appear inKirby's Dream Land 3. R.O.B. is a gray robot that debuted as a physical peripheral for theNintendo Entertainment System, which is used to playStack-Up andGyromite. Professor Hector is a human with a white mustache and balding head who debuted as the player character inGyromite.
R.O.B. had different color schemes when released in Japan (where it matches the tan and red colors of the Famicom) and when released internationally (where it matches the gray colors of the NES). Its appearance inKirby's Dream Land 3 has a unique design that incorporates elements from both color schemes, featuring a gray body with red accents, so that it would not need to be changed for international releases.
The two are found inSand Canyon - Stage 6, where Professor Hector will give Kirby aHeart Star if he retrieves all of R.O.B.'s parts in the stage.