Toad's name has been changed from Mortimer Toynbee (as he is known in the comics) to Todd Tolensky
DEBUT: Professor X/Charles Xavier, Cyclops/Scott Summers, Jean Grey, Nightcrawler/Kurt Wagner, Storm/Ororo Munroe, Wolverine/Logan, Magneto/Magnus, Mystique/Raven Darkholme, Duncan Matthews and Toad/Todd Tolensky. (episode 1.01 "Strategy X")
DEBUT: Rogue and Destiny (episode 1.03 "Rogue Recruit")
DEBUT: Blob and Tarin (episode 1.04 "Mutant Crush")
Blob is watching a loosely disguised version of The Powerpuff Girls on TV (episode 3.11 "Dark Horizon Part 1")
DEBUT: Forge (episode 1.06 "Middleverse")
Toad's theme (which we've seen in episode 1.01 "Strategy X", 1.06 "Middleverse" and 3.04 "The Stuff of Villains") now has lyrics. You can hear them during Toad's first fight with Nightcrawler, and at the end when Toad heads back to Wanda (episode 3.07 "The Toad, the Witch and the Wardrobe").
DEBUT: Caliban (episode 3.01 "Day of Recovery")
DEBUT: Mesmero (episode 2.10 "Mindbender")
When the X-Men and Acolytes are separated in the beginning, there was a reason why the writers had Nightcrawler, Colossus, and Shadowcat as a group. In Marvel Comics, they were members of a Europe-based team called Excalibur (episode 3.12 "Dark Horizon Part 2").
DEBUT: Colossus, Gambit, and Pyro (episode 2.16 "Day of Reckoning Part 1").
DEBUT: Scarlet Witch (episode 2.15 "The HeX Factor")
Boom Boom leaves the Brotherhood. (episode 2.15 "The HeX Factor")
DEBUT and only appearance of: Captain America (episode 2.14 "Operation: Rebirth")
Captain America is the only Marvel Superhero to cross over with Evolution, and is the second superhero referenced during the course of the series. The first being a small Iron Man in-joke from the episode 2.09 "On Angels Wings".
DEBUT: Angel (episode 2.09 "On Angel's Wings")
DEBUT: Juggernaut (episode 1.09 "Survival of the Fittest")
DEBUT: Spyke and Quicksilver (episode 1.05 "Speed and Spyke")
DEBUT: Havok (episode 1.12 "The Cauldron Part 1")
The Cytorrak gem Magneto uses in his enhancing chamber were the same ones that turned Cain Marko into the Juggernaut in the comic books (episode 1.13 "The Cauldron Part 2").
DEBUT: Henry McCoy as the blue furry Beast (episode 2.05 "Beast of Bayville")
CAMEO: Arcade. He is seated next to Kitty (episode 2.01 "Growing Pains")
First time we hear Gambit speak (episode 3.04 "The Stuff of Villains")
Powr8 is a copy of the real drink Powerade (episode 3.06 "X-Treme Measures")
Kurt arrives wearing a brown robe. In the comics, Kurt Wagner was briefly a priest, though he never wore a brown robe (episode 1.01 "Strategy X").
DEBUT: Shadowcat, Avalanche and Sabretooth. Technically, Sabretooth appeared in the first episode. However, he has a bigger role in this episode (episode 1.02 "The X-Impulse").
The US version got a new opener from this episode onwards (episode 3.10 "X23").
The Kids WB said this was the start of a new season of X-Men Evolution (episode 3.10 "X23").
The "Evolution" counterparts to the five original X-Men (Angel, Beast, Iceman, Cyclops and Jean Grey) are assembled here for the first time (episode 3.09 "Under Lock and Key").
The five-featured X-Men in "Under Lock and Key" (Beast, Angel, Cyclops, Ice Man, and Jean Grey) are not only the original five X-Men from the comic book series. They are also the original five members of another mutant team called X-Factor. The character of Apocalypse, whom this team of X-Men is trying to stop from being unleashed, first appeared in the X-Factor comic series.
Though Angel helps the X-Men in this episode, he still does not join the team (episode 3.09 "Under Lock and Key").
Mastermind has joined the Acolytes while Boom Boom has returned to the New Mutants (episode 3.09 "Under Lock and Key").
Jean's original code-name is Marvel Girl (episode 3.09 "Under Lock and Key").
This is the first time the X-Men, the Brotherhood and the Acolytes all fight on the same side (episode 3.11 "Dark Horizon Part 1").
Jean chooses Genetics as her major, since in the movie; she was a doctor in genetics (episode 3.11 "Dark Horizon Part 1").
The giant statues that attacked the mutants were representations of the highest Egyptians Gods: Anubis the Jackal God; Horus the Hawk God; Thoth the Ibis God and Apophis the Snake God (episode 3.12 "Dark Horizon Part 2").
The X-Men assembled by Xavier are the X-Men from the Dark Phoenix saga (episode 3.12 "Dark Horizon Part 2").
As episode 3.11 & 3.12 "Dark Horizon Part 1 and 2" was the original Season Finale for season 3, the X-Men are not vacationing after those events; the episodes are just out of order (episode 3.13 "Cruise Control").
Episode 4.01 "Impact" takes place two weeks after episode 3.11 and 3.12 "Dark Horizon Part 1" and "Dark Horizon Part 2".
Magneto and Mystique meet their apparent end in episode 4.01 "Impact".
It is revealed Magneto is holding Colossus' family hostage. That is why he is working for Magneto (episode 4.01 "Impact").
Magneto and Mystique were removed so the four mutant groups (X-Men, New Mutants, Brotherhood and Acolytes) could unite under Xavier against Apocalypse (episode 4.01 "Impact").
First reference to Senator Kelly's Mutant Registration Act (episode 4.02 "No Good Deed").
Marks the returns of Agatha Harkness since her first appearance, along with Wanda from episode 2.15 "The Hex Factor" (episode 4.01 "Impact").
The Acolytes are not in this episode (episode 4.02 "No Good Deed").
Principal Kelly is now running for mayor (episode 4.02 "No Good Deed").
Cameo: [Vi Daniels] Spyke's mother, was on a train (episode 4.02 "No Good Deed").
Starting with episode 4.01 "Impact", the title is no longer aired on-screen at the beginning.
Rahne and Jubilee have been removed from the New Mutants. It is unlikely that they will ever return (episode 3.03 "Mainstream"). We see them in Professor X's vision drawn from Apocalypse at the very end of Episode 4.09 "Ascension II." Magneto "tosses" a gold metal ball to Rahne, and we see the back of Jubilee's head next to Amara aside Bobby's ice slide. This is, presumably a practice session for the New Recruits.
One of the masks worn by the vandals, bears a suitable resemblance to the classic Marvel Comics monster, Fin Fang Foom (episode 3.03 "Mainstream").
Blob is reading an X-Men comic when Gambit walks in at the end (episode 3.04 "The Stuff of Villains").
Spyke leaves the X-Men and joins the Morlocks (episode 3.06 "X-Treme Measures").
Rogue joins the X-Men (episode 1.07 "Turn of the Rogue").
During Rogue and Magneto's magnetic "dog fight", they pass by a massive skyscraper with the letters SE lit up. The SE stands for Stark Enterprises, an Iron Man reference (episode 2.09 "On Angel's Wings").
DEBUT: Bolivar Trask and the Sentinels (episode 2.16 "Day of Reckoning Part 1").
DEBUT: Jean uses Cerebro (episode 2.16 "Day of Reckoning Part 1").
At the beginning of the final scene, at the swimming pool, the first few notes of background music are taken from the theme tune of the older Fox "X-Men" animated series (episode 1.05 "Speed and Spyke").
Kitty is seen sleeping holding a stuffed dragon. In the comics, Kitty has a pet dragon named Lockheed (episode 1.10 "Shadowed Past").
Episode 1.12 "The Cauldron Part 1" is the first time we see Mystique demonstrate her fighting skills. In the comics, she was a skilled assassin who could kill a man with her bare hands.
The first and only time 2 mutants go into one of Magneto's metal pods together (episode 1.12 "The Cauldron Part 1").
DEBUT: Principal Kelly, the school's new principal, assigned after the disappearance of Mystique. In the X-Men comics, Kelly is a senator involved in mutant affairs who was ironically killed by a human after being saved by the X-Men (episode 2.01 "Growing Pains").
Alex has his adopted name, Alex Masters, throughout the series, which was made for this show. In the comics, he is Alexander Summers and is the younger brother of Scott (except in Ultimate X-Men where he is the older brother of Scott). Alex has only had one other name in all his years of comicdom and that is Alex Blanding (only in X-Factor v1 #-1).
Kitty is shown lighting a Menorah in the ending montage, establishing that she is Jewish (episode 2.09 "On Angel's Wings").
Wolverine has two motorcycles. He uses one when he is in uniform (the blue sleek one) and one when he is in his street clothes (the red one).
In the comic book, Avalanche's name is Dominic Petros and he is of Greek descent.
The first sketch of Spyke was very different from this one. His name was Armadillo and had black hair. The second sketch he had black cornrows, but was still called Armadillo
Cartoon Network versions remove the teaser from episode 1.11 "Grim Reminder", unlike the other episodes where it is played after the title sequence.
The play used in episode 1.08 "SpykeCam", "Dracula: The Musical" is a real play and can be ordered through playbook catalogues. The song used, however, is an original song made for the episode.
DEBUT: Arcade. In the comics, he was an assassin for hire who used giant games to kill his targets (episode 2.04 "Fun and Games").
In Season 3 and 4, the opening for the show is totally revamped, and now includes Beast.
In the comics and on the old cartoon show, Storm became the leaders of the Morlocks. She gave up her leadership role of the Morlocks a while back in the comics.
There is now a character called Spyke in the comics: First Appearance: X-Force v1 #121. Last Appearance: X-Force v1 #128. Powers and Abilities: extend thin spines from his skin to various lengths or launch them away from his body at high speeds
The title of episode 3.07 "The Toad, the Witch and the Wardrobe", is a reference to the novel "The Lion, the Witch and the Wardrobe", the second of C.S. Lewis, "Chronicles of Narnia" books.
Pietro is watching a loosely parodied version of "The Crocodile Hunter". A snake is biting the guy when the camera cuts away (episode 3.07 "The Toad, The Witch and The Wardrobe")
In the comics, Mastermind was a member of Magneto's first brotherhood.
Sometime after Wanda left The Brotherhood in the comic books, she joined "The Avengers" alongside Captain America, Iron Man, and Thor becoming a mainstay and one of the cores in the team.
The writers of the show have admitted that they were big Buffy fans. Using Shadowcat as the catalyst, the two shows, Buffy and Evolution, are uncannily similar. A teenage girl with super powers, fights bad guys with super powers while at and to save her high school. Buffy/Shadowcat have opposition against her with first the School Principal and then the Mayor. Ironically, Joss Whedon, creator of all things Buffy, admits he is a fan of X-Men, and based the character of Buffy on Shadowcat, even giving her the surname of Shadowcat's team leader: Summers.
Pyro in the X-Men comics was an Australian named St. John Allerdyce. When not running around with whatever evil mutant group du jour there was, he made his living as a journalist and writer of trashy romance novels.
Beast's, and Marvel Comic's, translation of Apocalypse's true name is incorrect; in Arabic, "En Sabah Nur" translates to "The Seven Lights".
The dance Boom Boom does, in episode 'Walk On the Wild Side," as Rogue approaches the balcony railing was mimicked from Jessica Alba's dance in Never Been Kissed.
The character Spyke is not a part of the comic book based Marvel Universe and was created solely for this show.