Blast Barrel

A Blast Barrel,  also known as an Auto-Fire Barrel,  Auto-blast Barrel or Cannon Barrel, is a common type of Barrel Cannon that appears throughout the Donkey Kong Country series. It is represented by a symbol on the side of the barrel depicting a white outline of an explosion.

Donkey Kong Country series
Blast Barrels first appear in Donkey Kong Country. When a character jumps into a Blast Barrel, it automatically launches them in a predetermined direction. The Blast Barrel can launch the Kongs at great distances and often allows them to reach a location that cannot be reached by other means. The Kongs cannot control when or in what direction they are fired, as the launch is purely automatic. In Donkey Kong Country, Blast Barrels are also used to send the Kongs to bonus rooms or near the end of the level; the Game Boy Advance version and sequels replace them with Bonus Barrels and Warp Barrels, respectively, although Blast Barrels with the former's functionality are reused as of Donkey Kong Country Returns.

Blast Barrels lack the explosion symbol in Donkey Kong Land 2 and Donkey Kong Land III. The steel rims on their entrances are also colored white in those games as well as Donkey Kong Land, Donkey Kong Country 2: Diddy's Kong Quest, and Donkey Kong Country 3: Dixie Kong's Double Trouble!. In Donkey Kong 64, all Barrel Cannons look like Blast Barrels, even though only a few function like them.

Blast Barrels return in Donkey Kong Country Returns, Donkey Kong Country Returns 3D, Donkey Kong Country: Tropical Freeze, and its Nintendo Switch port, looking and acting the same as in the original version of Donkey Kong Country. These games also contain Blast Barrels with skull heads displayed on them, which instantly self-destruct after they launch the characters.

Mini Mario & Friends: amiibo Challenge
Blast Barrels also appear in Mini Mario & Friends: amiibo Challenge, where they are present alongside Barrel Cannons in Barrel Blast Jungle and one level of the Star World. They function just like in the past games, automatically shooting a character in a certain direction once entered.

Mario + Rabbids Kingdom Battle
Blast Barrels appear in the Donkey Kong Adventure mode of Mario + Rabbids Kingdom Battle. They can be used by pressing while standing next to them, and are used to launch Donkey Kong, Rabbid Peach and Rabbid Cranky to a certain part of the area they are in.

During the final battle with Mega Rabbid Kong, the heroes must unlock and reach a golden Blast Barrel to deliver the final blow to Mega Rabbid Kong.

Mario Kart Tour
A Blast Barrel makes a cameo on the Barrel Hanafuda glider in Mario Kart Tour, which itself uses the same Blast Barrel artwork from Mario Hanafuda.

Trivia

 * In Tanked Up Trouble of Donkey Kong Country, one Blast Barrel self-destructs as it fires the Kongs (predating those of Donkey Kong Country Returns), but only in the original version.
 * In the Donkey Kong Country television series, there are TNT Barrels that bear a resemblance to Blast Barrels.

Reference
Kanonenfass