Grandpa Beagle, also known as Blackheart Beagle, is one of main antagonists alongside Flintheart Glomgold and Magica De Spell in Donald Duck comics. He is the grandfather, founder, and sometimes leader of the Beagle Boys.
- Brazilian writers depict him as a respected semi-retired crook who sometimes gives advice to the Beagle Boys.
- Italian writers show him directly leading the Beagle Boys, and while they tend to turn his schemes into failures, he has some patience with them because, well, they are his grandchildren.
- Don Rosa portrays Grandpa Beagle as one of the greatest villains in Duckburg, even capable to assemble an alliance of Scrooge McDuck's enemies in "A Little Something Special".
He first appeared in the Carl Barks stories The Fantastic River Race (as Blackheart Beagle) and The Money Well (as Grandpa Beagle). He served as the main villain of the Don Rosa stories in the Ducktales comics even leading a villain team up in a comic special.
He made a cameo in the 2017 Ducktales reboot episodes McMystery at McDuck McManor in a painting and in Last Christmas in a Scrooge's past, voiced by Eric Bauza. In "The Fantastic River Race" and The Life and Times of Scrooge McDuck, Blackheart Beagle looked very similar to his present-day grandkids, albeit with a long mustache, a black and blue uniform and sailor hat. In "The Money Well" he looks like an old Beagle Boy with the number 186-802.
Grandpa Beagle is used again in 1962 by Rodolfo Cimino, as the Beagle Boys' leader, in the story Zio Paperone caporale d'assalto. In Italian stories, Grandpa Beagle has the word "Grazia" instead of a number, indicating that he may have been pardoned. Sometimes he is portrayed in the same physical shape as his grandchildren, sometimes thinner, and sometimes he's thin when all the Beagle Boys are shown as such.
- He sometimes appears smoking a corn pipe.
- Just like John D. Rockerduck, Grandpa Beagle was used only once by his creator Carl Barks, but became popular in Italian comics.
- It is unknown if Barks intended or not that Blackheart Beagle from "The Great River Race" and Grandpa Beagle from "The Money Well" were one and the same or not, but Don Rosa made them the same guy in "The Life and Times of Scrooge McDuck".
- There's a character in Mickey and the Roadster Racers/Mickey Mouse Mixed-Up Adventures whose also called Grandpa Beagle. However, he's a totally different character from Blackheart Beagle, especially since that Grandpa Beagle isn't even an antagonist, but an elderly man who simply likes to enjoy life at its fullest.