They act like vertical ropes from the original Donkey Kong Country, except disappearing and reappearing constantly. These ropes can help Diddy and Dixie Kong to reach high places and get across pits. Ghost Ropes indicate they are about to disappear by flashing before disappearing. The Kongs will fall, potentially to their doom, if they are holding onto the rope when it disappears.
Donkey Kong Country 2
Donkey Kong Land 2
In Donkey Kong Country 3: Dixie Kong's Double Trouble!, there are similar entities called Ghost Barrels.