I've seen it a hundred times, its like an upgraded version of those guns (i call 'em BFG's) that wario browser and ganondorf used to "trof-ize" every one.
also it took me like 10 trys to beat tabuu, just use guys that can hit hard or rapidly and can move fairly quickly, like pit or meta knight, oh and.... don't play with your five year old brother, he eats up your players >:(