Traveling to Australia makes Hong Kong seem right next door.
And it was worth the trip to see the Great Barrier Reef.
We wouldn't be here if Shaggy and Scooby weren't top-seeded...
in the sandcastle contest.
- I owe it all to my trusty teammate. - Me too.
You guys are amazing.
It's a sand tree-house.
The tricky part's the tree.
This is one time our vacation is going to be pure vacation.
These will do for a start.
I'm reading about the Great Barrier Reef.
Doesn't it boggle your mind that there are prehistoric creatures down there?
Anything before the creation of TV dinners boggles my mind.
Nothing like one-man volleyball.
- I always win. - Nice.
But you also always lose.
Like, some of these sand shacks are pretty darn good.
I'll take that as a grand accolade.
Frankie Martin here. I call my creation "Italian Rena-sands."
Like, very cool.
I'm Shaggy and this is Scooby.
The Shaggy and Scooby?
Didn't you do the actual working sand roller-coaster?
Well, it only had one loop.
You blokes are good.
But I have to warn you right now...
nothing's gonna stop me from winning this competition.
Except maybe that.
Guess our beach party comes with a soundtrack.
Hey, stop it, you blighters.
This is Sandcastle Beach.
I'm sorry, but we were told it's Beach-A-Palooza Beach.
And my band needs to practice.
Jeepers, it's Smash Mouth, and you're Steve Harwell.
- You're my favorite. - Thanks.
Why can't we have music and sand building?
Because the sounds destroy our masterpieces.
And we were here first.
But we came as invited guests.
- Well, now you're invited to go. - Hey, peace, mates.
We can all work together here in harmony.
Welcome. A voice of reason.
You keep your decibels low, we'll keep our walls thick.
Yeah, right. Yeah, okay. Yeah, right.
Hey, you're Rama Yam, in charge of the castle competition.
We've entered to build King Arthur's castle...
with a drive-through seafood window.
We call it "Clamalot."
- When do we start? - Right after our warm-up yoga exercises.
Please, join us.
Like, I always thought yoga was named after a bear.
We must prepare our inner harmony for agility and creativity.
- Excellent downward-dog position. - Thanks.
That coral. It's coming alive!
Those three kids, they just disappeared.
- Sucked under the sand. - Where's that coral thing?
- It's gone. - Maybe we should disappear.
Back to the U.S.A., where the only danger on the beach is painful sunburn.
Not yet. You've got a contest to win, and we've got a mystery to solve.
We should be safe in here for tonight.
Tomorrow we're working on the drawbridge and a guard tower.
- Awesome detail. - Thank you.
- Hey, we better see what's going on. - Great idea, Freddy.
When you find out, we'll be right here hiding.
First time we've ever worn out a monster.
Rama Yam, are you all right?
Yeah. I ran out when I heard the screaming.
Then I saw the coral creature.
And then three more sand builders disappeared.
- Where? - Right where you're standing.
What's this?
My medallion.
Reckon I lost it in the scuffle.
- What does it say? - That's Sanskrit, mate.
Ancient Hindu writing.
- It means "universal harmony." - Dude.
- What's all the ruckus, dude? - Where'd you come from?
Oh, we've been here all day riding in the gnarly waves.
We've been here all day too.
How come we haven't seen anybody surfing?
That's because— Shawn, that's my sore toe.
Then zip it, Shawna.
While you were surfing did you notice anything weird?
- Sure did, dude. - Disappearing teenagers?
Flat surf. That's when we came in for some Z's.
Wow, dude. Catch that wave.
- Banzai! - Banzai!
Hope it's safe enough for us to rebuild our castle.
Yeah, me too.
Look at all the footprints in the wet sand.
And paw prints.
And there's bird prints and crab prints and monster prints and—
- Monster prints? - Monster prints?
Double yikes!
The sandcastle's destroyed.
- Help. Help. - Jinkies.
Don't worry, we'll help.
No, "kelp." We're stuck in seaweed.
It's pulling them into the water.
Not if I can help it.
Just when it thought it was safe to go back on the beach.
That thing doesn't seem to breathe well out of water.
Maybe it lost this.
Some kind of breathing tube.
Looks like there's something more than coral behind all this.
Well, I'd sure like to know what it did to those kids.
- Me too. - Which kids?
The ones that look like big sand-drip castles, except without the castle part.
- Where did you see them? - Right over there.
This wet sand is just wet sand.
These rocks are really gross.
They're coated with algae.
That means they've been brought up from under the sea.
I have a feeling there's a reason.
- And I have a feeling it's a scary reason. - Yeah, me too.
I'm reading about coral.
It's a living skeletal thing that can grow as big as an island.
But not one word about coral that can walk.
Like, it looks like you and Scooby and I are the only ones left in this contest.
Well, don't prepare any speeches, mates.
Because after I finish the fountains with the dancing waters...
I'll have the winning entry.
At least today you've been able to work in peace.
Who did that? Who's responsible?
- Or not. - Crikey, what's bugging you now?
Come see for yourself.
You guys come too. I need witnesses.
What happened here?
Those were the band's instruments.
Now how are we supposed to perform?
And tomorrow's the concert.
Guess your little show will have to wait.
There's only one person that could've sunk this low.
And guess what? It's not me.
Though I do like the peace and quiet.
And the sculpture shows a certain Miami Beach mixed-media style.
Keep trying to control the beach, and you're asking for more trouble.
You can't scare me away.
So none of the band members disappeared...
but almost all of the sand builders have.
I can't believe a band would go that far just to play in the Beach-A-Palooza.
Over there! Come on!
Help me!
- He's gone. - We need to find out...
where these disappearing people are disappearing to.
That means it's time for a plan. Does anybody have one?
That's usually your department.
Just thought it would be polite to ask. Now, here's my plan.
Why can't somebody else put their life on the bait line?
As much as we'd love to, the target seems to be sand sculptors.
And you two are our only sand sculptors.
See these blips on the navigational screen?
That's you and that's Scooby.
You'll be under constant surveillance.
We're behind you no matter where you're taken.
Taken? What makes you think that we're gonna go along with this?
Your backpacks each have programmed compartments...
containing time-released Scooby Snacks.
Like, you drive a hard bargain, Freddy.
Like, I think there's only one thing we wouldn't do for Scooby Snacks...
and that's go without Scooby Snacks.
Yeah, that makes sense.
But it looks like we would offer ourselves to a horrifying coral creature...
and be yanked down under a beach...
only to be turned into disgusting sand-drip monsters.
- Let's go back. - Yeah.
I got them. I got them.
- I don't got them. - There they go.
That thing ran out of breath.
Like, help!
I'll get you out, Scoob, if it's the last thing I do.
No, the last thing I do is scream.
Shaggy!
- They're gone. - Don't worry, guys.
We'll track them. Their blips are in great shape.
Hey, dude and dudette.
Dude, you saw us.
Once again, spotted near the action.
Totally. Swells must've been 10 feet high.
You two say you're surfers, but nobody ever sees you in the surf.
We better tell them, Shawn.
See, dudes, you might find this hard to believe...
but we're upside-down surfers.
- You're what? - It's our invention.
Yeah, see, you bind your feet underneath the board...
and breathe through this special snorkel.
It's totally like being part of the wave.
Gives new meaning to the words "hang 10."
Under the curls was really tubular tonight...
but then we saw this big, coral skeleton thing...
- ... and we knew we had to get out. - Yeah.
We might've caught one wave too many.
Look, Shaggy and Scooby's blips are moving.
Out to sea.
Somehow they're right under the Great Barrier Reef.
Scooby-Doo, you're a sand-drip monster.
So are you.
Hey, guys, like, where are we?
Looks like nobody can talk but you and me.
Good thing we have these Scooby Snacks or I'd be really scared right now.
The gang should find us soon.
Hopefully before the snacks run out.
Whatever's going on here, let's just play along, Scoob.
Okay.
According to the screen, they're directly below us.
Velma, are you sure you wanna dive?
For Shaggy and Scooby, yes.
And to actually see the Great Barrier Reef.
We're in some sort of tunnel.
And we're not alone.
The sand-drip sand builders.
And there's Rama Yam.
Shaggy and Scooby. They're sand-drip monsters.
Like, don't mind us, outsiders.
We are humble zombie-ized workers, who are, by the way, out of snacks.
- They're fine. - But how do we get them out?
Not to mention us.
A challenge with a simple solution.
A plan using only objects found in this tunnel.
It seems like it could use just one more thing.
How about this?
A challenge with an even simpler solution:
Run!
The tunnel's collapsing.
Turn around, toward the beach.
No, Scooby!
Scooby, watch out.
Swim, buddy.
It saved Scooby.
Like, Scoob, old buddy, old pal, how are you feeling?
Wet.
Everyone made it.
Including the person behind all this beach badness.
And I think I know just who it is.
It's getting away.
The real monster isn't going anywhere.
That's Rama Yam?
Actually, Spencer Johnson.
I realized he was faking that trance when he started yelling commands...
to his muddy minions.
And this is how he got them that way.
Yes, master.
So why would you do such awful things to those nice kids?
They were working for the greater good of mankind, building the reefway.
Like, I've never heard of a reefway.
It would've been the Ninth Wonder of the World.
An underwater highway for cars, buses, trains, anything that rolls.
- Connecting Australia to New Guinea. - Ingenious.
Insane, but ingenious.
So when you couldn't do that legally...
you lured the best teenage builders here with that sandcastle contest.
You dragged us down through the wet sand...
and made us all look like sand-drip monsters.
Then you hypnotized them and put them to work.
That's what snapped us out of the trance.
Guess we were saved by the snacks.
He faked his disappearance so he could supervise his laborers.
He made them dig out rocks from the ocean floor...
and pile them at night on the beach.
Well, I would've gotten away with it if it weren't for you meddling sand-drips.
But what about that coral creature?
That's all it is, coral.
You mean for once, the monster's real?
It's no monster.
Lots of strange creatures have evolved under the Great Barrier Reef.
The sounds of undersea building probably confused it and drove it out of the deep.
Well, now that tunnel's shut down forever.
It won't be bothered anymore.
Thank you, coral creature.
Hey, we wanna welcome the sand builders back...
and to thank you for letting us play some mellow sounds...
guaranteed not to crack your castles.
Congratulations, Frankie.
Like, nothing could top your sand villa.
Except maybe the six-foot fudge-ice-cream-cone sculpture...
with sand-dripped sprinkles that Scoob and I just made.
Now, where is it?
Scooby-Dooby-Doo!