They ask us this every time the theme song plays, but how well do we really know the sponge who lives in a pineapple under the sea? SpongeBob SquarePants hit the airwaves in 1999 and took the world by storm.

The creativity, hilarity, artistic integrity, and nuance of a show about a sponge with square-shaped pants changed the landscape of cartoon history forever. The show was created by Stephen Hillenburg, a marine biologist and former creative director of Rocko’s Modern Life. Hillenburg

Irreverent and brilliant, SpongeBob had a solid three seasons on Nickelodeon and a theatrically released movie before the quality began to wane. The series may not be what it once was, but ten seasons and counting of a kids’ show is not a feat to be taken lightly. A lot of secret controversies can accumulate in 18 years of broadcast… let’s unearth the darkest secrets from the bottom of the sea.

Are you ready, kids?! Here are the 15 Dark Secrets You Never Knew About SpongeBob SquarePants.

15. Patrick and Gary are first cousins

SpongeBob SquarePants Patrick and Gary 15 Dark Secrets You Never Knew About SpongeBob SquarePants

Gary, SpongeBob’s snail who acts like a cat, and Patrick are friends. Why shouldn’t they be? Gary is SpongeBob’s pet, and Patrick is SpongeBob’s best friend. What you may not know about Patrick and Gary is that they’ve got more in common than SpongeBob. In fact, Patrick Star and Gary the snail are first cousins. That’s right. It’s Pluto-Goofy syndrome taken to a whole new level. 

According to the season 4 episode “Rule of Dumb”, Patrick’s father (Herb) and Gary’s father (Sluggo) are brothers, making Patrick and Gary first cousins. This was revealed in the first season that series creator Stephen Hillenburg left.

In his wake, the show was somewhat… well– how to say this delicately– changed, and not in a good way. The brilliance was gone, but surely SpongeBob served as a perfectly good show for young children who didn’t know any better, right? 

14. SpongeBob got in trouble for being a sailor mouth

SpongeBob coming out of his kitchen after eating his sundae 15 Dark Secrets You Never Knew About SpongeBob SquarePants

SpongeBob was deemed by many parents as an unsuitable show for children far before Hillenburg and his team left. In fact, there’s been controversy since way back after the 15th episode of season 2 (Hillenburg stayed on until the end of season 3 and the first movie).

The episode in question, called “Sailor Mouth”, featured SpongeBob and Patrick overhearing Mr. Krabs using a curse word (bleeped out with dolphin sounds in the episode). Not knowing that there were “bad” words that they shouldn’t use, the friends proceeded to use it all over Bikini Bottom to much outrage from the aquatic townsfolk.

A watchdog media group called the Parents Television Council (PTC) spoke out about the episode as promoting and satirizing vulgar language, one of the first public denouncements of SpongeBob by a conservative parental group.

According to the PTC’s report,  this episode  was an attempt to promote and satirize profanity usage among children. The report came out in 2005, several years after the episode originally aired in the 2001-2002 season — the same television season that the PTC named as one of the best children’s television programs on air.