https://youtu.be/p01QJz7ryvg 4:15 starts explaining how the attack he is using is intended to destroy everything including the planet and saitama "Collapsing Star Roaring Cannon (崩星咆哮砲, Hōsei Hōkōhō): While in his meteoric burst form, Boros can launch a massive beam of energy from his mouth which is much larger than his average Energy Beam. The color is also different, instead of being only blue, it has golden tones to it. Boros states that he needs to concentrate and release the entirety of his latent energy to perform this technique. The beam is powerful enough to be able to destroy a planet." translation from the boros description page from the manga adaption [url=http://m.imgur.com/9iEFgm7?r]here[/url] Probably the most proof anyone on the forums has given