Spongebob was born in 1999.
Spongebob's name was originally supposed to be SpongeBoy, but the name was already copyrighted... for a mop.
Spongebob was created by Stephen Hillenburg. Hillenburg wanted to make sure that the word "Sponge" was retained in Mr. SquarePants' name so children wouldn't mistake him for a large chunk of cheese living under the sea.
Pineapples are used commonly in tropical decor, but Stephen Hillenburg also imagines that SpongeBob would just like the way living in a pineapple would smell.