Bringing Up Baby is a classic 1938 Screwball Comedy directed by Howard Hawks, and starring Katharine Hepburn, Cary Grant, and a leopard.Milquetoast paleontologist David Huxley (Grant) is about to be married and is only missing one piece of his Brontosaurus skeleton (the "intercostal clavicle"). The night before his wedding, he's supposed to butter up a rich widow's lawyer so she'll donate a million dollars to the museum. Things take a rapid turn for the worse, though, when he meets scatterbrained heiress Susan Vance (Hepburn), who accidentally steals his golf ball, and then his car, preventing him from finishing the meeting. After the evening ends with Susan braining the lawyer with a rock, David vows that he never wants to see her again.The next morning, Susan calls David on the telephone. Her brother in South America has mailed her a tame leopard called Baby, and she enlists David to help her transport it to her aunt's farm. Then, having made up her mind that David is the man she's going to marry—though he doesn't know it yet—she does whatever comes to mind to keep him there. It turns out that Susan's aunt is the potential museum donor, so they have to conceal David's identity and the presence of Baby, while also hunting for the intercostal clavicle, snatched up and buried by the dog.Then Baby escapes, and so does a man-eating leopard from the circus, leading to several cases of mistaken identity as multiple groups of people go leopard-hunting in the forests of Connecticut. Everyone ends up in jail (briefly), David's fiancee rejects him, and the dinosaur skeleton is destroyed, but David confesses his love for Susan at last, and the movie ends with their happy, if still scatterbrained, embrace.
Artistic License - Paleontology: There is no such thing as an intercostal clavicle. There can be no such thing as an intercostal clavicle. "Intercostal" means "Between the ribs", and the clavicle connects the rib cage to the shoulder girdle.
Science Marches On: The clavicle in question comes from a brontosaurus, which, even at the time, was recognized by the scientific community as Apatosaurus.
Artistic License - Physics: It's not clear what causes the ladder to swing back upright after Susan and the latter tilt over sideways.
Aww, Look! They Really Do Love Each Other: This is even lampshaded by Susan after David says something unspeakably rude about her to her face. She stops, gives that beautiful smile that only Katherine Hepburn could give, and launches herself into his arms, shouting, "Oh David! You really do love me!" David tries to play it cool, but finally admits it.
Can't Have Sex, Ever: David's Disposable Fiancé mentions that their marriage must entail no domestic entanglements of any kind: "Yes, David, I see our marriage purely as a dedication to your work."
Cardboard Prison: David casually exits his jail cell when he gets exasperated listening to Susan babble at the constable. He even briefly gets the constable to join him back in his cell, before the cop realizes what has happened and has the cell locked up for real this time.
Clothing Damage: To David's coat and then Susan's dress in the nightclub scene.
Cloudcuckoolander: Doesn't even begin to describe Susan. She spends most of the movie perpendicular to reality.
Susan: (after breaking a heel off her shoe) I was born on the side of a hill.
Comically Missing the Point: David tells Susan she has to leave her apartment after he finds out there's a leopard in it. She says she can't, because she has a lease.
The Pratfall: David slips on an olive Susan dropped and falls really hard on his butt.
Real After All: A running theme. First it is David who doesn't believe that Susan is harboring a leopard in her bathroom and later it is the Sheriff who doesn't fall for the "leopard story". Cue this trope.
Susan also tells the police that David is really 'Jerry the Nipper'; this was the nickname of Cary Grant's character in his previous film The Awful Truth. David lampshades this by protesting that Susan is making everything up out of movies she's seen.
Unplanned Crossdressing: After David Huxley ends up wrestling a leopard in the middle of a pond, he returns to Susan Vance's home where she loans him her very girly robe while his clothes dry out. Susan's aunt, Elizabeth, is less than impressed with his wardrobe choices.