Boss Dumb Drum

Bumble B. Rumble is the boss level of Kremkroc Industries, Inc., the fifth world of the game Donkey Kong Country. The Kongs must beat the titular Oil Drum, Dumb Drum, to progress to Chimp Caverns.

SNES
As with all world boss fights in Donkey Kong Country, the fight takes place in an arena filled with bananas, in this case within a single screen; and if the player enters with a single Kong, a DK Barrel is instantly broken to ensure they start the fight with both Donkey and Diddy.

The battle starts with Dumb Drum attempting to crush the Kongs by floating in the air and slamming itself down on them. If Dumb Drum misses the Kongs, it will begin to release two enemies out of its body. It will release the following enemies; Kritters, Slippas, Klaptraps, Klumps, and Armies, in that exact order.

If the Kongs defeat these enemies, Dumb Drum will attempt to crush them again at a faster pace after each round and tries to do so once more for every wave beaten (ex.: after the Kritters are beaten, it will do so twice, after the Slippas, three times, etc.)

Once the Armies are gone and with all his enemies spent, Dumb Drum crashes to the floor, defeated, and the Kongs recover a fifth Giant Banana.

Game Boy Advance
In the Game Boy Advance port, the Kongs have to throw a TNT Barrel (which will appear after taking out the enemies) at Dumb Drum while it tries to crush them (though it does not speed up) to damage it. It only tries to crush the Kongs once each time, and if they miss, it releases the enemies again.

When defeated, Dumb Drum will self-destruct, giving Donkey Kong and Diddy Kong access to Chimp Caverns.