[s3e21] The Life And Crimes Of Scrooge Mcduck! -

: Scrooge upstaged him during a treasure hunt in 1987 and left him stranded in a cave with sharks (explaining his modern-day shark obsession).

: We see a young Ma Beagle whose father was a small-time con man until Scrooge out-swindled them and took the deed to Duckburg. [S3E21] The Life and Crimes of Scrooge McDuck!

If you're looking for more analysis, check out reviews from Den of Geek or Bubbleblabber for deeper dives into the lore! If you'd like, I can: : Scrooge upstaged him during a treasure hunt