Ogilvey was a crewmember of Davy Jones's ship, the Flying Dutchman. Like the rest of the crew, over time he grew to look like a sea creature. In his case, he grew to resemble sea coral. He wields one pirate sword.
When Will Turner became the captain of the Dutchman, Ogilvey was reverted back to his human form, although this does not happen in the video game.