I love you all to death (Just so I can smash bros with you) (SSBWiiU/3DS)

[[robo9]]

I think that's just his new Aerial A Forward attack just really close to the ground. Like as soon as he jumped the player pressed A Forward. As you noted it looks like he's jumping to use that attack. Or it could be his new Forward Smash Attack being used without a charge.

I'm not too sure, his short hop would have to be ridiculously short for that to be the case. I could see it being an uncharged smash, but then I'd be disappointed if they got rid of his superpowered headbut.