This story is just an alternate potions scene from Scooby Doo Monsters Unleashed
The two friends were riding down an elevator after escaping the two skeletons
"Wowee Scooby Doo." started Shaggy "We're onto something"
Soon the elevator touched down and the two friends got out of it. But quickly turned around as the elevator started going up.
"This place is like cluetopia Scoob!" says Shaggy
"Reah!" answered Scooby
Shaggy checked out a table full of beakers and lab equipment then walked to a rusty door. Meanwhile Scooby rushed over to what seems like a fridge.
"Refigerator!" Scooby exclaims then looks back so Shaggy won't notice him and he opens the fridge. He instantly spots a yellow potion. "Mmm. Remonade!" He slurps it up not caring about it's jelly like texture.
Suddenly the left side of his face expands outwards, then the right side, soon his whole head grows bigger. This expansion continued untill he was an alien monster.
"Check it out. Look at those weird letters Scoob!" Shaggy turns back and looks at Scooby in shock
"Raggy?" Asked Scooby as he burped and his belly expanded outwards making him a fat alien
"Scooby doo. You've turned into a monster" Shaggy pointed at him.
Scooby looked into the mirror on the fridge and screamed dropping multiple potions.
"You don't eat stuff that glows!" Shaggy takes away the last potion he had in his hand and puts it back in the fridge. "There's got to be an antidote here somewhere" Shaggy pulls out a darkblue potion "Here Scoob this looks medicinal"
Scooby takes it without question, spilling some on Shaggys hand in the process.
Shaggy notices the potion on his hand and licks it off as Scooby drinks the potion
"Tastes like-" Shaggy is cut off as he and Scooby start to spasm uncontrolably. Scoobys eye stalks even twist together
Then after a 'ding' both stop spasming. "Strawberries!" Saggy says
Quickly Shaggy looks in the mirror "I'm okay Scoob!" he exclaims.
Suddenly two popping sounds can be heard as Shaggy now has a shocked face. Shaggy was shocked at the fact that he now has a womans body. A sexy one at that, slender arms, big breasts, thick thighs and all.
Shaggy turns towards Scooby and says "I've got a chicks body!" as he looks at Scooby he lets out a shocked scream.
"I'm the rasmanian revil!" Scooby says as he starts spinning
Shaggy not wasting any time turns back to the fridge and starts looking while swaying his hips. He finds a glowing yellow potion which he throws away. Soon after he picks up a light blue potion and splashes Scooby with it and drinks some from it.
Soon after he hunches over 'I think I'm gonna puke!' Suddenly he is forced up as his left arm explodes with giant muscles. 'Holy hell!' His train of thought ended as his right arm too exploded with muscles. His boobs exploded into heavy pecs, from there his legs expanded with muscles and lastly his crotch area bulged out. 'Holy fudge cake. I'm..I'm'
"Check it out dude! I'm buff!" He flexed as he said that.
Scooby stopped spinning to reveal a sexy and thicc black woman instead of Scooby. "Oh my! I feel so good~" she said.
As Shaggy saw the woman who was Scooby he started doing all kinds of poses.
"Damn you're big my guy" She said checking out Shaggys body.
"Check out my pecs sexy gal!" Shaggy said as he flexed his giant pecs, tearing his green tank top in the process.
"Mm~ you're even better now big guy~" she said walking around him. "I say we deserve a drink," she said taking out a pink potion from the fridge "What do you say?"
"Let's do it sexy chick!" Shaggy said taking away the potion and drinks half of it giving it back to Scooby
"Okay love~" she drinks the other half. "I like the taste big gu-" before she could finish, both of them started to shake and dance uncontrolably.
Shaggy grabbed his head as glasses appear on him along with a lab coat.
Meanwhile Scoobys woman body gained a ton of muscle.
"Checkit out dude! Now I'm buff!" Scooby laughed as she flexed her new muscles.
"My god! It seem I've become extremely inteligent!" Shaggy grabs two potions and starts mixing them together.
"It's awful! I long for the blissful ignorqnxe of my former self." Shaggy said while Scooby was flexing and posing. "Flexing, checking out pecs, flirting with a transformed Scooby. Those were wonderful times" Shaggy says shaking the two potions.
"Check out these tits buff geek!" Scooby said flexing her muscular breasts.
"Hush now buff madame. This is a highly combustibly synthesis." Shaggy said as he finished mixing the potions
"A what?" Scooby looked at Shaggy dumbly.
"Take this beefbrain" Shaggy splashes Scooby as he drinks the potion
Suddenly both of their muscles deflate as Scooby transforms back into a dog. Shaggy wasn't so lucky as he transforms into a woman.
"Aw man not again! Can this get any worse?" Shaggy asked.
But as just as he finished talking his breasts and butt expanded like they were filled with silicone, his hair turned platinum blonde
"Like!O.M.G! I look so sexay!" She looked at herself in the mirror.
"Raggy?" Scooby asked worried.
"Like who's 'Raggy'? I'm Cindy! Bye bye dog thing!" she Rode up the elevator leaving Scooby behind.