Shaggy The Monster! is the sixth episode of Scooby-Doo! And The Paranormal Adventures.
It's lunch break and the gang is in the cafeteria. Scooby and Shaggy are eating while Velma tries to do her homework. Shaggy suddenly stops eating to see a girl and he falls in love with her. The girl introduces herself as Amanda Lair. The plane flies above the school and a bottle falls out. Shaggy and Amanda talk to each other and, after getting to know each other better, they become a couple. Daphne's comment about Shaggy having a girlfriend makes Velma feel a little jealous. The bottle lands on the window and it cracks. A mysterious slime leaks into Shaggy's sandwich and he eats it. Shaggy starts to feel weak and the gang takes him to his bedroom. Velma says that Shaggy may be sick, so the gang decides to let him take a rest. Amanda arrives and says that she'll take care of Shaggy. The gang returns to cafeteria to find the cracked bottle with a part of the slime on the window. The gang goes to the school lab and checks the slime. Velma discovers that the slime is dangerous and it can turn anyone into a monster. The gang then hears Amanda's scream and they run to Shaggy's room. They find Amanda covered in a goo. Then, the gang is covered in goo. Shaggy then appears in a monstrous form. Shaggy then escapes. The gang manages to escape and free Amanda. Shaggy destroys the school and attacks anyone in his path. The gang arrives to catch Shaggy. Shaggy escapes and the gang chases him. They go outside. It's starting to rain. Shaggy screams and falls into the ground. Shaggy then changes back to normal and Velma realizes that the rain reversed the effects of the slime. At the end of the episode, Shaggy is heartbroken after receiving a message from Amanda saying that their relationship is over.