In the Rocky Mountains, Shaggy was fighting the Phantom Shadows with one hand. The skinny eater just watched as his hand hit the phantoms' faces until they knocked them down, he didn't move his hand, his hand moved him.
Shaggy: * Yawn* "Well, I thought this would last longer" –he said while looking at the unconscious phantoms.
At that, the Frankenstein Monster ran towards Shaggy to catch him, but in a single movement he put his elbow where the monster's chest until he knocked it down the coast and gave him some finger movements that made him paralyze for the moment.
Shaggy: "Uhm... it seems that this does not end" –he said while looking in front of him.
Creeper appeared and was about to attack until he observed his fallen comrades and then looked at Shaggy who with a twinkle in his eyes managed to scare him away.
Shaggy: "Come on, give me everything" –he said as he went into combat mode.
Creeper, having nothing to do to him, gave a hiss that made the ground shake and skip grains of earth, but Shaggy did not flinch and looked at who would be his last opponent: the Phantosaur.
Shaggy: "Well, it looks like you're not a hologram" –he said deftly.
The Phantosaur roared loudly and ran over to Shaggy to trample him and he did, the footfall so hard it made the ground crack. Creeper celebrated for that, but the celebration lasted very little as the phantosaur's foot began to lift itself and the reason was one thing... Shaggy activated his Ultra Instinct mode. Glowing with his green aura and eyes the same shade as his aura, his hand made a push and that sent the phantosaur flying until it crashed into a mountain of earth. Creeper watched in horror as the phantosaur rose from the dust and began to roar and ran towards Shaggy.
Shaggy: "Let's get this over with" –he said while cracking his fists.
Its speed was so fast that it made everything around it slow until in seconds it was back to normal with Shaggy having his left fist against the ground while the phantosaur stayed still until he fell to the ground abruptly, totally defeated.
Shaggy: "Wait..." –he said as he disappeared into view of someone.
Creeper looked from side to side until receiving a strong blow to the neck caused by Shaggy who was behind him.
Shaggy: "Looks like I'm done with my work" –he said as his eyes returned to normal and his aura disappeared.
Shaggy began to walk away from all the fighting until he found his friends who were waiting for him. His pet and best friend Scooby-Doo ran to him.
Scooby-Doo: "Raggy, where were you?"
Shaggy: "Oh, I was just walking around Scooby" –he told him.
Fred: "Good gang, time to go" –he told everyone.
The gang got on the Mystery Machine and headed for their next destination. They all talked about what they would do next while Shaggy pondered his body to have enough strength in case he ran into a dangerous adversary, but one thing was for sure: Shaggy is not afraid of the supernatural, the supernatural is afraid of Shaggy.
-The end-
So far this One-Shot ends in commemoration of the 10th anniversary of the movie Scooby-Doo: Legend of the Phantosaur on September 6, 2011, and also for the Shaggy Ultra Instinct meme.