B. Locker

B. Locker is a character in the game Donkey Kong 64. As his name suggests, he blocks the Kongs from reaching new levels. He will let them pass if they have a certain amount of Golden Bananas. B. Locker looks like a big sign post with eyes and three number panels for a mouth. While B. Locker is not really an enemy, he does work for King K. Rool (although unhappily). That is mainly because if B. Locker were to disobey K. Rool and allow for the Kongs to pass without the bananas, it would be the end of his life ("The big sawmill in the sky").

Golden Bananas
In the game, B. Locker blocks the entrances to each of the levels, only letting the Kongs in if they have collected a certain total number of Golden Bananas (shown by a counter on his teeth). Once they have enough, he leaves that level's lobby, allowing the Kongs entry to the level. The Golden Banana requirements to pass him in each level are:
 * Jungle Japes: 1
 * Angry Aztec: 5
 * Frantic Factory: 15
 * Gloomy Galleon: 30
 * Fungi Forest: 50
 * Crystal Caves: 65
 * Creepy Castle: 80
 * Hideout Helm: 100

Trivia

 * B. Locker's name is a pun of Blocker.
 * There is a glitch where Lanky Kong can pass through B. Locker without having the proper amount of Golden Bananas.