In Calvin and Hobbes, when Calvin becomes terrified after accidentally breaking his father's binoculars, he wonders if he should run away, or commit hara-kiri, with Hobbes quipping that perhaps he should do both. A shockingly dark joke, that would never have been allowed to be published in newspapers, had it not been an obscure term for a suicide method involving disemboweling oneself.
The original April 4, 2005, comic strip for has Bucky listing the different animals eaten for different holidays: "Christmas turkey, Thanksgiving turkey, Valentine's Day beaver..." Later reprints changed "beaver" to "marmot".
Another series in Get Fuzzy featured two ghost hunters showing up at the main characters' apartment; they represent Atlantic Research of Supernatural Entities. If this wasn't clear enough, their initials appear on their shirts and, later, their laptop (in a larger font than any of the dialog lettering).
Bucky once owed money to the Chipmunkfia (Chipmunk Mafia), and received a note that said "Pay up or we will turn you into a nut sack." Reprints have replaced it with "nut case".
In one For Better or for Worse strip, Elly's friend Anne looks at a newspaper filled with personal ads for "swinging couples looking for partners", and says she wouldn't do something like that because it would require her to "lose at least 20 pounds". It was surprising that newspaper editors would let a specific reference to "the lifestyle" on the comics page in 2009, much less when it originally ran in 1980.