As i once said during Onigashima Raid.
Hole made for Big Mom & one made for Kaidou were Foreshadowing of Ennies Lobby & Whirlpool next to it
Big Mom was sent down there by Kid's Canon which was a Reference to Pluton
O-Tama was reference to Poseidon & Momo was a Reference to Uranus who had same Power as Main Villain
In other words:
Pluton was used to defeat Story's Main Secondary Villain, creating Ennies Lobby Hole
And it's Trapped there, why it can't get out? Cuz of Sun that never disappears, Ennies Lobby is Island that never Sleeps
Indicating that it's a Villain who needs Darkness & can't emerge under Sun (Blackbeard......)
And it also reveals that long ago, the Sun did Disappear, which is why Elbaf celebrates Rebirth of The Sun
Poseidon is simply Mermaid who was able to control Main Villain's Army
In other words, Sea Kings were created to be Main Villain's Army, but a Mermaid was able to take control of them (Just like Tama & Gifters)
Main Villain of Story has Power of Uranus & is related to Whirlpools
Which means......
Also i said it long ago & i will repeat it again, Vegapunk's Weapon is a Modern Version of Pluton, just like Shirahoshi inherited Poseidon's Will, Vegapunk inherited Intellect of Person who once built Pluton, that's why He was born Smart
I need to add that Kid, Momo & Tama who represented Ancient Weapons during Raid, share the fact that all Three were almost Killed by Kaidou, He destroyed Momo's Home & left him to Die (But He survived), then He sent a Subordinate to Destroy Tama's Village, then He got Introduced on Kid's Island
Destruction of Tama's Village is Reference to Destruction of Enies Lobby, and just like Kaidou attacked Kid's Island, Main Villain of Story is finally gonna be Introduced attacking Vegapunk's Home (Egghead). Get ready