Combo Cannon

Main Cannon #2 is the main gun of Battleship Halberd, Meta Knight's personal warship. This weapon goes by several English names:
 * It is called the "Combo Cannon" in The Arena of the original Kirby Super Star and its Trophy in Super Smash Bros. Brawl.
 * It is also called the "twin cannon" in the English version of Kirby Super Star and renamed "Main Cannon #2" in Kirby Super Star Ultra
 * It is called the "Gravity Disruptor" in the English dub of the anime.
 * Its Japanese name is usually rendered 2連主砲, which means "Main Gun 2," although it also goes by Combo Cannon.

It is a cannon located on the topside of the Halberd, usually near the front (although in Kirby: Squeak Squad, it is on the second-highest level of the ship). Its name suggests another cannon of its firepower elsewhere on the ship; later designs of Halberd feature a very long cannon, the largest on the ship, on its bow - this is presumably Main Cannon #1.

Kirby Super Star and Kirby Super Star Ultra
It is an elaborate double-barrelled gun turret that fires cannonballs from its main (upper) barrel and lasers from its smaller (lower) barrel. This smaller barrel can be destroyed separately from the main assembly to keep it from shooting any more lasers. It has a mechanical arm that will try to grab and throw Kirby, drop bombs on him, or try to hold him in front of the firing laser. Every other time it prepares to fire its laser, a platform will rise under Kirby to try to move him into the way of the blast although this was changed to a low-health reaction in Kirby Super Star Ultra. When it was first destroyed, it exploded and shattered pieces of bent metal everywhere, with a strong enough force to wreck most of the top of the Halberd.

Inhaling the large cannonballs and bombs dropped by the hand give Kirby Bomb (although the former inexplicably grants Yo-yo in the SNES version). If Kirby has the Ice or Fire copy ability, he can jump above the lower cannon when the top cannon is facing backward so he can use his ice/fire breath to shut it down.

Kirby's Epic Yarn
The cannon has been turned into yarn along with the rest of the Halberd, and Kirby fights it now with the Starship. The cannon's arm is not present, so it no longer tries to grab Kirby or drop bombs on him. The top cannon shoots large cannonballs in successions of three while the bottom cannon still fires the laser beam that are a lot wider than the ones of Kirby Super Star (Ultra), which is now made up of several strands of yarn. UFOs periodically enter the fray and fire lasers at Kirby.

The insignia on the side of the cannon is Meta Knight's symbol. Its design was changed in Kirby Super Star Ultra and Kirby's Epic Yarn.