The Fusion Dance, or Fūsion Hā if you're fancy, is a technique that temporarily merges two bodies into a single superior form.
The result of a correctly performed Fusion Dance is a superior being. The power level is multiplied several times that of the individual fusee.
The results of an incorrectly performed Fusion Dance are rather unsavory...
If one of the poses are off, this can lead to a weaker, obese form.
If the timing is off, this can lead to an even weaker, sickly looking form.
But what if, not only both the timing AND the poses were off, but it was performed outside of it's realm of origin, between two humans with arguably fragile DNA?