Characters: Osmosis Jones
Osmosis "Ozzy" Jones
Voiced by: Chris Rock
- Cool Car: Had his cop car customized.
- Cowboy Cop
- Dogged Nice Guy: Has trouble winning Leah Estrogen's affections. He does at the end, though.
- The Hero
- In-Series Nickname: Always known by "Ozzy".
- Nice Job Breaking It, Hero: He did the right thing causing Frank to vomit, thereby saving him from a contaminated oyster, but it caused Frank to lose his job and the respect of the local community, and got Ozzy suspended for "use of unnecessary force".
- Official Couple: With Leah at the movie's end.
- Protagonist Title
- Red Oni, Blue Oni: The red to Drix's blue.
- Sensitive Guy and Manly Man: The Manly Man to Drix's Sensitive Guy.
- Sesquipedalian Smith
- Shapeshifter Showdown: What saves him against Thrax.
Voiced by: David Hyde Pierce
- Arm Cannon
- The Big Guy
- But Not Too White: Drix is played by David Hyde Pierce. The producers were looking for someone as white-bread as possible. Niles Crane is about as white-bread as you can get.
- By-the-Book Cop
- Captain Ersatz: Drix bears a strong resemblance to Iron Man.
- Genius Bruiser
- An Ice Person
- The Lancer
- Red Is Heroic: His main colors are red and yellow.
- Red Oni, Blue Oni: The blue to Ozzy's red.
- Sensitive Guy and Manly Man: The Sensitive Guy to Ozzy's Manly Man.
- The Smart Guy
Voiced by: Laurence Fishburne
- Ass Kicking Equals Authority: He gets the bacterias to accept him as their leader after he single-handedly killed their boss.
- Badass: Thrax might be a horrible, sinister individual, but there is no denying he is good at what he does. Aside from his bodycount, he is shown to have great fighting skills, easily defeating a bunch of bacteria and their boss.
- Badass Longcoat: One he can even use as a glider.
- Big Bad
- Deadpan Snarker
- Establishing Character Moment: The first thing he does upon being introduced is to casually murder two harmless workers, at least one in an incredibly gruesome way. He then proceeds to burn their entire boat by merely scratching its surface with his index while he is walking.
- Evil Is Petty: Only partially. Thrax wants to kill Frank in a record time so he can be in medical textbooks.
- Family-Unfriendly Death: He falls into a vat of alcohol, which of course has very deadly effects on germs... although to be fair this tends to be how irredeemable villains tend to die...
- Also applies to the first cell he kills. What he does to the bacteria mob boss too, though to a lesser degree.
- Faux Affably Evil
- Glory Hound: See Evil Is Petty. Thrax is like a serial killer who's trying to become famous in the most brutal fashion.
- Nice Job Fixing It, Villain: In the final battle with Ozzy, he use the black chain holding the hypothalamus chromosome to try and choke him. But then Shane blinks, separating the two with the chain still around Ozzy's neck. His final attack failing thanks to Ozzy's morphing abilities seal the deal.
- Omnicidal Maniac
- Kill It with Fire/Playing with Fire: His finger-nail claw pretty much burns whatever he scratches to a melting, burning lava mess.
- Knight of Cerebus
- Red and Black and Evil All Over: Red-skinned, dressed in black, and definitely evil.
- Scary Black Man: Only in voice (Laurence Fishburne does it).
- Serial Killer: He keeps trophies from his victims and reminisces about them.
- Vile Villain, Saccharine Show: And how. It's jarring how such a vicious, murdering villain managed to stick in an otherwise light-hearted comedy.
- Villainous Cheekbones
- Walking Wasteland/Touch of Death: His left index finger causes any organic matter it touches to combust or explode.
Voiced by: William Shatner
- Fat Idiot
- Laser-Guided Karma: Abolished Ozzy for having Frank throw up to get out an evil virus. Then at the end when he's been booted out of office, he presses a similar button and winds up flushing himself right out of Frank's own body.
- Mayor Pain: Type B.
- My God, What Have I Done?: Doesn't say it but his reaction as the city of Frank burns down around him pretty much has this trope all over it.
- Obstructive Bureaucrat: Let's see, he fired Osmosis and gets Drix out of Frank just for popping a pimple without permit (Which is like blowing up a building in the real world) and as mayor control's nearly all of Frank's actions, including his slovenly behavior. Said neglect needless to say, almost ends up killing the guy and every cell with him.
- Sleazy Politician: To the tee.
- Too Dumb to Live
Voiced by: Brandy Norwood
- The Chick
- Graceful Ladies Like Purple: Her suit and even her body are both purple.
- Living MacGuffin: Is taken hostage by Thrax, and very nearly killed by him.
- Non-Mammal Mammaries
- Office Lady: Works as a secretary for Mayor Phlegming.
- Official Couple: With Ozzy in the end.
- Sassy Black Woman
- ShesGotLegs: That mini-skirt isn't helping the fact that she has long legs.
- The Smurfette Principle: Although Leah isn't the only female anthropomorphic cell in Frank's body, she's the only one with Nominal Importance.
- Tsundere: Type B.
- Women Are Wiser
Francis "Frank" DiTorre
Played by: Bill Murray
- Bumbling Dad: He means well, and does care about Shane, but he has a major selfish streak. Though this is mostly due to Mayor Phlemming overriding his body for his own ends.
- Children Raise You
- "Fantastic Voyage" Plot: The plot takes place inside Frank's body
- Fat Idiot
- Guys Are Slobs: Played straight and subverted, as in a flashback we hear Shane complain that neither he or Maggie, his wife, take care of themselves very well, Frank just got worse after Maggie died.
- The Mourning After: Still mourning the loss of his wife, Maggie. Justified, as it seems to be a relatively recent loss.
- One of the Kids
- Perma Stubble
- Straw Loser
- Too Dumb to Live: What kicks off the whole plot as he eats an egg that was inside the mouth of a monkey and got spat out onto the ground. Yeah that seems sanitary.
- Vomit Indiscretion Shot: Double Subverted; we don't see it actually happen (although we hear him retching, the focus is on the horrified crowd at the science fair), but we do see a picture of him puking all over Shane's teacher.
Played by: Elena Franklin
- Broken Bird
- Calling the Old Man Out: Blames Frank and his unhealthy habits for Maggie's untimely death, and calls him out for deciding to take her to a chicken wing Fan Convention instead of the hiking trip she was looking forward to.
- Children Raise You: Takes care of her dad, because he doesn't take care of himself.
- Deceased Parents Are the Best: Averted; she misses her mom a lot, and is rather distant from the other kids at school. Taking care of her dad doesn't help either.
- Gender-Blender Name
- Missing Mom: Her mom died of an unspecified illness. Though it's implied she was as unhealthy as Frank has been throughout the movie.
- Only Sane Man: Female version.
- Women Are Wiser