They have the bad characters from Wacky Races. I recognized the guy in the suit and the dog, only because I grew up watching Wacky Races as a child (just turned 20) . I don't know why they mixed the characters in the new Scoob movie but somehow it worked
Reading one other comment I read, the evil man from the other show is a Hanna Barbara reference. So is the old theme song and reference to older shows, just to tell what's to come.
They may be different characters, yes, but kids nowadays can learn and see what we grew up on.
Another comment is just saying how "horrible" The movie is. they have no clue to the references and why it's being made. Like did y'all know the guy who did shaggy wasn't going to be the old shaggy for the voice.
But this is what I know and hope you enjoy it. It showed the relationship between shaggy and Scooby . First a cartoon, it
made me emotional