Something funny in setting of gelatin

• Catchphrase
• Slogan putting liberal in a stew
• "In space no one can hear you scream," for "Alien"
• Genitals mostly involved as point of joke
• "Just do it" for Nike
• "Good night, and good luck," e.g.
• Identifying phrase

Wiktionary Word definitions in Wiktionary
n. 1 The punch line of a joke. 2 (context computing English) A pithy quote habitually appended to a signature, used as an advertising slogan, etc. 3 A line attached to a draft of cargo or a container to provide control and minimize pendulation of cargo ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"punchline of a joke," 1926, originally "last line in an actor's speech" (1916), from tag (n.1) + line (n.).

Wikipedia Word definitions in Wikipedia
In entertainment , a tagline (alternatively spelled tag line ) is a short text which serves to clarify a thought for, or is designed with a form of, dramatic effect . Many tagline slogans are reiterated phrases associated with an individual , social group ...