In the "Rocky" film franchise, what is the name of Rocky Balboa's dog?

In the first Rocky film, the fighter was given the dog Butkus by Adrian the petshop owner. The dog was actually Sylvester Stalone's real dog and at one point he was so poor he sold Butkus for $25 and later bought him back for $15000!

https://www.pethealthcare.co.za/PetFriendly/Articles/sylvester-stallone-and-his-dog-butkus

Butkus was large Bull Mastiff actually owned by Sylvester Stallone in real life. The story of Stallone selling the dog and rebuying later appears to be a hoax.

Sometimes he sold Butkus for 30 $ and bought him back for 3,000 $ after one week.
https://einfachtierisch.de/hunde/suesse-hunde/sylvester-stallone-verraet-aus-geldnot-den-hund-verkauft-37763

Sometimes he sold Butkus for 40 $ and bought him back for 15,000 $ after one year.
https://www.tvtoday.de/entertainment/kino-news/sylvester-stallone-so-krass-war-seine-geldnot-175754.html

And so on.... There is no evidence that the story is true.