From the Super Mario Wiki
The Birdo Ray was a large, seemingly unstoppable superweapon, and was an extension of Darth Koopa's Koop Star. Despite its name, the Birdo Ray does not resemble an actual Birdo; instead, it is named for the fact that it is a cannon that can fire an egg-shaped missile. The missile, if it were to have hit a planet, would have covered the surface in a yolk-like substance, presumably killing all life on the planet.
The Birdo Ray was featured in The Super Mario Bros. Super Show! episode "Star Koopa", where Darth Koopa threatened to destroy the Mushroom Colonists' Planet with it unless they were to surrender their planet to him. After capturing Princess Toadstool, Darth Koopa showed her, as well as Mario, Luigi and Toad, a simulation of the Birdo Ray destroying the Mushroom Colonists' Planet, implying that he wanted Princess Toadstool to order the Mushroom colonists to surrender.
As Princess Toadstool refused to surrender, Darth Koopa ordered Mouser to activate the Birdo Ray, which would fire after a thirty-minute charging time. After narrowly escaping from Koop Star, Mario's group made it to the Mushroom Colony with only fifteen minutes left until the Birdo Ray was set to go off. Obi-Wan Toadi explained that the only way to stop the Birdo Ray was for someone to penetrate Koop Star in a Mushroom Starfighter, so that they could disable it manually.
Mario and his friends agreed to help, and after fighting off enemy Stormtroopa Starfighters, Mario succeeded in blowing up the foundation of Koop Star with a Bob-omb. As a chain reaction, Koop Star as a whole blew up, taking the Birdo Ray with it, just as it had finished charging.