Molecular cannon

The Molecular cannon is a weapon from the Generation 1 continuity family.

Brawl's just there because he's drawn to heavy artillery.

Not a very subtle weapon, is it?Bruticus, "Fight or Flee"

The molecular cannon is a large weapon emplacement that obliterates a target and leaves a large explosion in its wake—like many cannons, really.

Fiction

The Transformers cartoon

A molecular cannon was constructed on the planet Paradron when the Decepticon Empire had conquered the Energon-rich world. The Predacons made use of the weapon to destroy an Autobot shuttle that was approaching the world - and, as incidental collateral damage, an entire moon that just happened to be in the way. Bruticus thought it made too loud a bang, whilst Galvatron believed that was why the Predacons enjoyed using it and was disappointed there wasn't anything left of the Autobots to make a souvenir. Fight or Flee