You see all kinds of resborbed twins from two head fish to the sort that twitch post (great photos btw). However keep in mind that Eugene said that the fillet of the fish near the "spot" in question was "normal".

Typically would expect the resborbed twin to more than a skin deep phenomenon.

I like Slab Happy have seen photos completely healed scars (months to years post injury) from lamprey "bites" that look very similar to that photo that started this discussion.

Curt