Danny also faces the typical challenges of a high school student while attempting to keep his ghost half a secret, except from his best friends, Sam Manson and Tucker Foley, and later his sister, Jazz.
The next day, Danny receives a D on his biology test, and Sam suggests that he earn extra credit by doing a report on the purpleback gorilla.
Jack brings his entire family to Wisconsin for his college reunion hosted by his old friend, Vlad Masters.
Already afraid that his parents might get divorced, Danny accidentally knocks Jack's wedding anniversary gift to Maddie into the Ghost Zone.
Guest Star: Matthew St. Patrick as Skulker A recently popular singer named Ember McLain magically enchants and charms teenage audiences with her hypnotic song.
When Danny feels he is losing, he steals the sword of the Fright Knight, the ghost spirit of Halloween, in an attempt to make his haunted house scarier.
However, the symposium proves a ruse by Vlad Masters to convince Danny and Maddie to stay with him and abandon Jack.
Danny and Valerie are forced to work together by watching a child-like flour sack for health class, but neither of them demonstrate willingness to help the other.
Many hired ghost hunters are parodies of other mystery shows, as Men in Black and Scooby-Doo are paralleled as teams bent on capturing Danny for Vlad.
Guest stars: Brian Cox as Pariah Dark, Michael Dorn as The Fright Knight, Peter MacNicol as Sidney Poindexter and Martin Mull as Vlad Masters As Youngblood continues to torment Danny, appearing as if Danny is fighting an invisible enemy and going crazy, Jazz decides a Fenton family vacation with no ghost hunting is the solution.
To show how "dumb and pointless" they really are, Sam signs up for a beauty pageant, in which Danny serves as the judge due to being the perfect "common, average and bland boy".
Little do either one of them realize this is all a plot from Dora the Dragon Ghost to find a wife for her arrogant elder brother, Prince Aragon.
As the two half-ghosts battle an enemy ghost together, Dani dodges questions from her curious relative; she feigns weakness and pretends to faint into Danny's arms after the fight.
Will Danny's friends abandon their hard feelings and come to his aid yet again, or will Vlad finally obtain the DNA sample he needs to clone his ideal half-ghost son?
As revenge on the men, Spectra, Kitty and Ember join forces and use their powers to make all males vanish from Amity Park.
A plant ghost named Undergrowth turns Amity Park into a literal jungle, in the process holding the citizens captive.
Danny must save Amity Park while also trying to keep his newly developed cryokinetic abilities in check with the help of his friend Frostbite.
After being humiliated and shown up by Vlad's team several times, Danny uses the Fenton Portal to remove his ghost half and decides to go back to a normal life, to the objection of his friends and Jazz.
Vlad sabotages the Fenton's plan to destroy the Disasteroid and he reveals his ghost half to the entire world in an attempt to gain world domination, but he fails when he discover the disasteroid is made from an element ghosts can't touch and flees into exile in space.
Realizing the mistake he made losing his powers, Danny comes up with a plan to acquire a massive force of ghost energy to turn the Earth intangible so the Disasteroid will harmlessly pass through it.
Danny Phantom announces his plan to the world and everyone works together to create a machine to turn the Earth intangible.
He gets a statue of his likeness erected in the capital city of every country in his honor and ends up finally dating Sam.
Danny, Sam, Tucker, and Jazz return to find some strange things emerging from the ghost portal.