One of the many flavored rums available, pineapple rum was probably one of the first (maybe right after coconut rum). Pineapple is one of the more logical flavors to pair with rum though usually this is done as part of a drink recipe with pineapple juice along with white or aged rum. But if you want it all in one bottle with some added sweetener you can find it in pineapple rum.
As usual for flavored rums, Cruzan's pineapple rum stands above the rest (though that's not saying much). At 54 proof it is drier and more balanced than the really sweet low proof examples.
You can make a far better product than you can buy in the liquor store though...just soak fresh pineapple chunks in rum overnight. Strain and add sugar if you wish, though this is optional.