Sodom

Sodom (ソドム, Sodomu) and Gomorrah (ゴモラ, Gomora) are the two gigantic King Bulls (sea horses in the most literal sense) owned by the Franky Family.

Appearance
Gomorrah is pink with red stripes and a green mane, while Sodom is yellow with a red mane.

Past
According to Chopper's translations, they were found by the Franky Family in the stomach of a Sea King they were eating. Fortunately, they were too full to eat the sea bulls too. So Sodom and Gomorrah swore loyalty to Franky forever since he saved them from the Sea King.

Enies Lobby
After the Franky Family asked if they could come with the Straw Hats to save Franky (to which Luffy told them to get on) they immediatly got Sodom and Gomorrah tied to a boat shaped like a House and then attached it to the Rocket Man afterwhich Sodom and Gommorah then kept swimming while the Rocket Man charged straght ahead untill Yokozuna (testing his strength) caused the train to go off course while also causing the Franky Family to become separated from them.

They then by found one of the Puffing Toms cars drifting through towards them where Usopp (as his alter-ego Sogeking) and Sanji were after they were sepparated from the Sea Train. They then rejoined the Straw Hats.

Unfortunately, Sodom is felled by a mortar shell (but tearfully begs the others, through Chopper's interpretation, to go on without him), and Gomorrah is taken down soon afterward by cannon fire. However Gomorrah, fueled by memories of Franky taking him and Sodom in and looking out for the two, manages to summon up his last ounce of strength and crashes through the Enies Lobby courthouse's courtyard before finally passing out from the pain. Without their assistance, the Franky family managed to make it as far as Enies Lobby's courthouse before being tied up by the Marines. The two were scooped up by Oimo and Kāshī and joined the Straw Hat Pirates allies' rush to escape and were loaded onto the Puffing Tom and brought back to Water 7.

Aftermath
Two days after the destruction of Enies Lobby, they are now back on their "feet" and well enough to join the Straw Hat Pirates' victory party.

Trivia

 * Their names are the same as the two cities Sodom and Gomorrah, which were famously corrupt. Both cities were destroyed by God in the Bible.