Yes, Mickey's dog Pluto had a son, the puppy star of
"Pluto, Jr." (1942), who gets into various mayhem, requiring proud poppa to come to the rescue.
Despite his obvious cuteness, the little tyke never made another film
appearance (nor, by the way, is there any mention of whom the puppy's mother
is), though in 1946 Pluto's sibling, K.B., starred in another one-off,
"Pluto's Kid Brother."