Davy Jones' locker is just a rusty gym locker that is filled with smelly socks. In the episodes, it seems to have green goo at the bottom of it. The purpose of it is to torture whoever is in it but it is most likely a notorious bad place for sea creatures.
The legend of "Davy Jones' locker" has existed in nautical folklore for many years, the first record being in 1726. In actual folklore, "Davy Jones' locker" is a phrase meant to refer to the bottom of the sea, where drowned sailors and wrecked ships end up. The name "Davy Jones" is likely a reference to the ghost of Jonah, the biblical figure who was swallowed by a giant fish, and was released by God after praying to be rescued. However, SpongeBob takes a different route, and uses the Monkees singer of the same name.
Role in series
"Born Again Krabs"
The Flying Dutchman threatens Mr. Krabs that he will be sent to the locker if he does not quit being cheap.
"SpongeBob SquarePants vs. The Big One"
The Flying Dutchman returns after Mr. Krabs ends up in his territory. He tries to send Mr. Krabs down to the locker, but after a brief fight between the two, The Flying Dutchman ends up in the locker, where he is tortured by Davy Jones, who throws socks at him.
"The Curse of Bikini Bottom"
The locker appears again. The Flying Dutchman also talks to someone named Davy on the phone.
The only two people seen taken to Davy Jones' locker are Mr. Krabs and SpongeBob in "Born Again Krabs," but neither were put inside it.
If Davy Jones was the official owner of Davy Jones' locker, that would mean that as of "SpongeBob SquarePants vs. The Big One" The Flying Dutchman kept Davy Jones' locker.