DB Chapter 304
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
"The Final Transformation" (超サイヤ人そして超フリーザ誕生！？, Sūpā Saiya-jin Soshite Sūpā Furīza Tanjō!?; Literally meaning "Birth of a Super Saiyan and a Super Freeza?!") is chapter 304 of the Dragon Ball manga.
Gohan wonders why Kuririn attacked Vegeta, as Piccolo yells that they should get out of here. Gohan helps the injured Piccolo fly away, and they land, and Gohan says Dende can heal him. Speaking of Dende, he tells Vegeta that he can't heal someone who has killed so many of his people. Vegeta weakly tells him that if he doesn't, they can't possibly defeat Freeza. But Dende flies off and Vegeta falls to the ground. Kuririn and Gohan are on their way to find Dende, and Kuririn explains to Gohan how Saiyans greatly power up from near death recovery. They suddenly spot Dende going in the opposite direction, and notice Vegeta hasn't been healed. Freeza continues powering up, and watches as Dende heals Piccolo, realizing that was how they'd been doing that. Piccolo wonders if he also has this ability, but Dende says no, because he's a Fighting-Type.
Kuririn tells Dende he must heal Vegeta, but Dende refuses since he's the same as Freeza. Piccolo then asks him to, because he can't even beat Freeza as he is now. There's suddenly a huge explosion where Freeza is, and Piccolo realizes Freeza's transformation is complete. Kuririn thinks they should hide somewhere, but Piccolo says Freeza would just destroy the planet, since he has no use for it now. Piccolo is pissed at how ridiculously huge Freeza's ki has become, Kuririn is worried, and Gohan asks Dende to quickly heal Vegeta. So Dende flies off, as Freeza's figure starts to come into view through the smoke. Vegeta is healed, and he shows his gratitude by kicking Dende. "Be thankful I didn't kill you!!" Vegeta notices Freeza's battle power, and figures he must finally be showing his true form. But Vegeta isn't worried, because he's now a Super Saiyan, or so he claims.
Freeza's final form is small, but smoothed out, and his tail has been healed. Kuririn isn't too worried the way Freeza looks now, but Piccolo says not to judge him by his outward appearance. "Damn... After all of the troubles you went through to have a wish granted by the Dragon Balls... Sorry... I don't seem to be much help to you guys..." Freeza then suddenly shoots a small blast, which goes past Piccolo, Kuririn, Gohan, and even Vegeta. The four of them turn around to find Dende lying dead. Piccolo freaks out that he barely saw anything but a flash of light. "Now there can be no more revivals..." says Freeza.