Skeleton Harvester, a giant monster who harvests people's skeletons. Appears infrequently, but his first appearance was iconic enough that he is one of Buttersafe's most famous characters.
Anti-Humor is fairly common in the dry world of Buttersafe. For example, "Fishing". The joke isthat from the text in the first panel you expect some sort of hilarious shenanigans to go down. You expect these shenanigans (of the hilarious variety) to go down right after the guy says he's got one - say, he has difficulty reeling it in, the boat capsizes, whatever - so when it cuts right to the elephant being sanguinely in the boat with no problems experienced at all (nor indeed any indication that this is at all outside the norm) this goes against your expectations, and thus humour is born.
I Love Nuclear Power: Parodied in a Running Gag where The Rant claims that some character got his powers by being bitten by the appropriate radioactive object. In full: Pie Man's "“Pie Senses” come from being bitten by a radioactive can of syruped peaches"; The Champion of Tattoos "got his champion tattoo powers from being bitten by a radioactive tattoo needle"; Big Glasses "got his Big Glasses Powers from a radioactive one-hour glasses store"; the paramedic in "Being a Hero" "got his CPR powers from being bitten by a radioactive paramedic"; and Surfing Turtle "got his surfing & crying powers from a radioactive ocean of tears".
Running Gag: Whenever a character with a superpower appears in the comic, The Rant will explain that that character got their powers from being bitten by a radioactive <something related to the power>. For example:
The God of Lightning got his lightning powers from being bitten by a radioactive lightning bolt.
Silly Reason for War: In "Thrift Shopping", a war breaks out between "Thissideland" and "Thatsideland" over ownership of a thrift-store bought sandwich.