Complex sentence: One of The Beagle Boys mentions that the Candy Striped Ruby will be theirs that is a reference to The Status Seeker where They steal the candy striped ruby from Scrooge.
Split into simpler sentences: One of The Beagle Boys mentions that the Candy Striped Ruby will be theirs. That is a reference to The Status Seeker where they steal the Candy Striped Ruby from Scrooge.