Jumbo Barrel
The Jumbo Barrel is a special airplane-shaped Barrel that is owned by Funky Kong in Donkey Kong Country.
If Donkey and Diddy Kong pay a visit to one of the six Funky's Flights on Donkey Kong Island, Funky will let them ride in his Jumbo Barrel to any area of the island that they've already visited, free of charge. As a means to prevent level-skipping, the Jumbo Barrel is unable to travel to any unvisited areas. Regardless, the Jumbo Barrel serves as the safer alternative to fighting bosses for traveling between the various areas of the island.
In the Game Boy Advance remake of Donkey Kong Country, the Jumbo Barrel can be found at Funky's Fishing. Once the Kongs have been there at least once, they can call Funky at any point on the map and have him pick them up in the Jumbo Barrel.
In Donkey Kong Country 2: Diddy's Kong Quest, the Jumbo Barrel is replaced with the Funky Barrel, which instead resembles a biplane. Although it serves the same purpose as the Jumbo Barrel, rides are only free once at each Funky's Flights II location. Afterwards, Funky will charge two Banana Coins per ride.
It is unknown if the Jumbo Barrel is one-of-a-kind, or if there are multiples.
