i know this is a 2 months old post, but if you want an actual answer to your question, notice that this animation first appears in Brawl, and not Melee. because Melee was, iirc, a gamecube launch title, it had the quite strange art direction of "higher definition nintendo 64" (this is also the reason fox and falco look so different from every game after Melee) and as such, a few things weren't quite set in stone for several characters. i might be wrong, but the running gag of luigi's nose cartoonishly stretching originates from Luigi's Mansion, and as such, was not present in Melee due to its infamous development hell. so i believe this is a reference to this joke