A common expression of frustration used in SpongeBob SquarePants actually contains a very clever and subtle double meaning. The charming innocence of SpongeBob SquarePants is undeniable. Its presentation, humor, and stories contain something to entertain practically every potential viewer, and the show is carefully written to appeal to the widest possible audience. There's a depth to SpongeBob's world that makes the show particularly enthralling, as it's enriched by years of world-building that make it an utterly fascinating show that has proved consistently entertaining.
Part of the show's charm includes its use of running jokes. Some of these, such as SpongeBob SquarePants's "My leg" joke stem from the repetition of absurdist humor, whereas others, such as Squidward always being miserable, were born of certain characters' individual traits. There are some running jokes that come from other places still, like the show's subtle references to topics completely unrelated to the story at hand.
One such joke is so incredibly subtle that it's easy to miss its clever double meaning. In lieu of traditional human curse words, the characters of SpongeBob SquarePants employ their own much tamer brand of bad language. When frustrated, characters often exclaim "tartar sauce!", and though it seems like a slightly morbid dead fish joke, there's also a secret double meaning that makes it one of the smartest and most subtle jokes in the entire show. It's actually a reference to Tartarus, a name for the Greek underworld, a place that draws interesting parallels with the show's setting.
Spongebob's Tartar Sauce Is A Smart Reference To Greek Mythology
As so many SpongeBob SquarePants characters have been heard making the same exclamation, it can be assumed that it's a fairly standard curse word in Bikini Bottom. However, "tartar sauce" sounds remarkably like Tartarus, better known as the name given to the lowest part of the Greek Underworld. Tartarus was originally the Underworld's Underworld, but later came to be synonymous with the Underworld as a whole. As the Underworld was essentially the hell of Greek mythology, it's clear which curse word SpongeBob's characters are using.
There's also a clever aspect to the joke regarding the location of Tartarus. As SpongeBob is set on the sea floor in Bikini Bottom, the reference to the lowest possible place is perhaps a nod to the show's location, too. As the seas and Bikini Bottom is SpongeBob SquarePants' whole world, it's a relatively subtle way of establishing its own version of hell by referencing Greek mythology (with a clever fish pun thrown in for good measure).
The use of "tartar sauce" as an exclamation of frustration is doubly clever because there are multiple levels to the implications of its use. Like with most human curse words, there's a clear history behind the expletive, except SpongeBob seems to take it a step further by creating a deep joke out of something inconsequential. By having its characters exclaim "tartar sauce" when upset, SpongeBob SquarePants simultaneously proves its brilliance and the depth of its comedy.