Cell's original, baby form floats in Dr. Gero's basement laboratory. In our present timeline, this "Baby Cell" is killed by Trunks and Kuririn when they discover the basement (which included some jinzôningen blueprints). In the future timeline, however, it grows to full-size, cracks out of the machine, kills Trunks (therefore stealing his time machine), and travels back to our present timeline in order to absorb Jinzôningen #17 & #18.

NOTES: FIRST APPEARS...

DBZ Episode 145; Manga Chapter 365 Baby Cell just sits in the tank, totally unaware of his surroundings, and the fact that he's about to be killed...

Cell first appears to us, already in first-form, absorbing every human he comes across in Ginger Town. Unlike his larva form, he now fully walks upright on two legs. His facial features have not yet fully developed, and still retains a "beak"-like mouth, rather than traditional human-like features seen in later forms. The two sections of his head shoot off in different directions, rather than nearly straight up as in the next two forms.

While in this form, Cell attains greater power by absorbing all of the people he comes across, regardless of their strength. Rather than fully absorbing people, though, he seems to suck the life out of them by stabbing them with the pointed end of his tail, which literally drains the victim of their body mass.

This Cell is from a future timeline where he has killed Trunks and stolen the time machine. He has returned to the past (our present timeline) in order to fully absorb Jinzôningen #17 and #18. By absorbing each of these, Cell will reach another stage (one at a time), ultimately resulting in his kanzentai ("perfect") stage. Until then, Cell absorbs all humans he comes across.

Note that, in the original Japanese version, Cell's voice does not change from form to form.

NOTES: FIRST APPEARS...

DBZ Episode 141; Manga Chapter 361 Cell's first stage is very lizard-like in nature, without many fully-formed facial features. Cell will need to absorb Jinzôningen #17 and #18 in order to reach the next two stages.

After absorbing Jinzôningen #17 (and a great deal of innocent humans), Cell reaches his second stage. In this stage, Cell's facial features begin to resemble a human's more and more.

While the nose is not yet fully formed (as it will be in the next stage), he now has an actual mouth. The two off-shooting sections of his head now go straight into the air, as well.

In this stage, Cell's power has increased exponentially, but he is still no match for the newly powered-up Super Saiyans. His rear end is handed to him by "Super Vegeta," who ultimately makes the mistake of letting his pride control him; Vegeta allows Cell to absorb Jinzôningen #18, thus completing himself and achieving his kanzentai ("perfect") form.

Note that, in the original Japanese version, Cell's voice does not change from form to form.

NOTES: FIRST APPEARS...

DBZ Episode 152; Manga Chapter 372 After having absorbed Jinzôningen #17, Cell takes on more humanoid facial features, and drastically increases in power and speed. He is still not yet a match for the fully-powered Super Saiyans, though...

When Vegeta allows Cell to absorb Jinzôningen #18, his absorption process is complete, resulting in the "perfect" form. Cell is an organic being in every way, now (or so he explains), complete with fully-formed nose and mouth.

Cell's power, in this form, is greater than that of even the Super Saiyans (Goku, Vegeta, Trunks). Vegeta and Trunks, even in their advanced Super Saiyan forms, are unable to so much as scratch him. Goku declares his first loss against Cell during the "Cell Games," leaving only Gohan to challenge the monster. Gohan undergoes a new transformation (into Super Saiyan 2, thanks to a great deal of Cell's physical and mental abuse, pushing Gohan over the edge) to battle Cell, ultimately defeating him.

Note that, in the original Japanese version, Cell's voice does not change from form to form. Also, the fourth daizenshuu writes "DEVELOPED FORM" under "kanzentai," but this is not quite as accurate a translation as "perfect form."

NOTES: FIRST APPEARS...

DBZ Episode 159; Manga Chapter 382 After having absorbed Jinzôningen #17 and #18, Cell has reached his "perfect" form. His power is far greater than any Super Saiyan's, and he has taken on the facial and body features of most regular characters.

Since Cell is comprised of the greatest fighters across the universe, this naturally includes many of the Saiyans (including Vegeta and Goku). Saiyans that are recovered from near death exponentially increase in power (as seen by Goku and Vegeta during the Freeza arc).

When a single cell of Cell's is able to live through the blast on Kaiô-sama's planet, it somehow "remembers" the structure of kanzentai Cell (remember that Gohan had kicked out #18, which resulted in Cell degenerating back into 2nd form before exploding). This cell completely resurrects Cell into a "super" kanzentai form; one that is not only "perfect," but also has a great power-up due to the Saiyan DNA! Cell appears to almost be in Super Saiyan 2, so to speak, due to the large amounts of energy and lightning that surround his body.

In the North American version of the Budokai video games, this form of Cell's is referred to as "power-weighted."

NOTES: FIRST APPEARS...

DBZ Episode 189; Manga Chapter 413 While not physically different from regular "Perfect" Cell, in his new "super" stage, Cell tends to have lightning surround him a la Gohan's SSJ2. His speed and power rival SSJ2 Gohan, as well, most likely due to the Saiyan cells in him allowing him to recover and increase in strength after near-death.