You remove three cards from the deck and leave facedown....
The King of spades, the JOKER, and Queen of Clubs
You turn your back and give your helper the cards and have her pick one and place another on top since the villian wears a mask.
You have your helper spell out SCOOBYDOO, 1 card for each letter and VELMA and place all on top of the MASKED Villian.
Now..comes the mathmatics
You claim Fred's favote card is the KING of Spades and you have your helper pick up packet, deal 1 card for each letter and drop rest on top.
You claim Shaggy is the JOKER because JOKERS are wild and have the spectator spell out ANY CARD
and drop the rest on top
Finally, Daphnies; card....
When all is said and done....
The Villian is on top....
Reveal in your favorite manner.

Could you explain it a little bit better? "Finally, Daphnies; card...." what is Daphnies card? The Queen of Clubs? Do you do the same thing with the Queen as the King? This might be a pretty good effect but I don't understand what the magic is. The participant's card or "villain" jumps to the top? Is that it? Because if that is what happens what is the significance of all the spelling? There are plenty of ways to make a card jump to the top of the deck without such a complex and tedious amount of spelling out cards.

Yes, Queen of clubs.
All spelling done the same and the magic is upto you.
On the table you have a pile of cards and some in your hand.
You claim the last card dealt is the villian....
It is not, but villian wears a mask...
At this point, you can do twirl change ect...

Being new to magic, I don't often have much to contribute to these forums, but being a children's librarian I can say with confidence: Lots of kids still read the heck out of Scooby Doo books! So for anyone wondering if "these kids today" would "get" Scooby Doo, lots of them certainly will!