None of the female members of Vilgax's race seen in this episode have chin tentacles. But Myaxx (from "Secret of Omnitrix") did have them.
Vilgax has red eyes, but his people have green eyes.
How can Ghostfreak still be alive? His remains were destroyed in Earth's atmosphere from "Be Afraid of the Dark".
Ghostfreak returns in this episode, but in his last appearance in the original series, he was reduced to ashes by the light of the sun.
Ben regains Ghostfreak in the Omnitrix, but in "Be Afraid of the Dark" episode in the original series, Ben regained him again.
Ben: (while waiting for Gwen on the miniature golf course) And five centuries later...
Kevin: This couldn't be a more obvious trap if there was a sign that read "free cookies"!
Ben: Probably... but I really like cookies.
Swampfire: (thinking Vilgax betrayed him, Gwen and Kevin to the Ghostfreaks) I can't believe you could trick us into... (sees Vilgax protecting a young Chimera Sui Generis girl from the Ghostfreaks) ...saving a little girl? Okay, now I feel like a jerk!
Vilgax: This is not over, Ben Tennyson. In fact, now that the secrets of the Omnitrix are mine, and there are none left to stop me, I'd say it's a rather auspicious beginning!
(as the Ghostfreak-possessed Ben attacks)
Gwen: Ben, stop it! You're hurting your friends! Please, I know you're in there, somewhere!
Vilgax: And that's exactly what I plan to take care of!
Vilgax: (about Ghostfreak) He tried to possess me.
Ben: He always was the possessive type.
Vilgax: "Burger Shack"?
Ben: I got you the kiddie meal, so don't let them know you're over eight.
Ghostfreak: Please, the light... burns!
Vilgax: And if I were to stop it?
Ghostfreak: Don't toy with me, Vilgax. Ask for what you want.
Vilgax: I do not ask, Ghostfreak. I demand, and you obey!
All but three of Ben's original ten aliens have been seen so far. Those discluded three being: Ripjaws, Wildmutt, and Stinkfly. However, he has only become three himself (Cannonbolt, Diamondhead, and Fourarms).
Another original alien, Ghostfreak, returns to the Omnitrix.
In the original Ben 10, Ben's Ghostfreak was unaffected by any light because of his protective sun-suit. But in this episode, the Ghostfreak minions were harmed by light, even though they wore similar suits.
It is revealed that Vilgax's homeworld is named "Vilgaxia", presumably in honor of himself. It also revealed that his people regard him as a benevolent and heroic leader.
Ghostfreak's DNA is once again added to the Omnitrix.
While fighting Vilgax, Ghostfreak demonstrates telekinetic abilities.
It appears that the energy beams Ghostfreak utilized in the Ben 10 episode "Be Afraid of the Dark" are not just restricted to his "full potential" form exhibited in said episode.
The minion-forms Ghostfreak turns Vilgax's people into resemble Ghostfreak's original, light-protected form, back when he was first part of Ben's Omnitrix.
Alien Form(s) Used:
Steven Blum does not reprise his role of Ghostfreak from Ben 10. Instead, Jeff Bennett voices him here.
The prison guards bear resemblance to the Manhunters, a group of robotic DC Comics villains.