There are a relatively small number of notable Batman fights in which the Dark Knight gets the short end of the stick, but that first throwdown with the Mutant Leader in The Dark Knight Returns was pretty bad.

So in a Gotham with no Batman to save it, that's a character who could pose a real threat, isn't it?

Well, some fans are speculating that this odd-looking villain captured by set spies near filming for Gotham's third season could be one of the Mutants, a street gang best known for their appearance in Frank Miller's masterpiece:

Ben McKenzie (Jim Gordon) e uma "criatura" no set de Gotham! #Season3 pic.twitter.com/hIPlYCJNF2 — Gotham Brasil (@gothamtvbr) July 8, 2016

Screen Crush thinks the actor is former Green Bay Packer Michael Montgomery, though they noted that neither FOX nor Warner Bros. Television would comment on that speculation.

In the comics, the Mutants didn't have actual spikes and...is that fur?...but such ornamentation wasn't uncommon in their strange clothing. The Mutant Leader had a mouthful of sharp canine-like teeth.

Fans who have seen the image responded "Godzilla," leading some to speculate as to whether this might be Killer Croc, but the spikes seem like a distinctly different character. It could, of course, be a new character created for the show -- especially if he's not going to return for multiple episodes, you don't want to kill off too many fan-favorite villains.

Batman villains Jervis Tetch (the Mad Hatter), Poison Ivy (with her age accelerated to make her more the seductress of the comics), the Court of Owls, Talon, and Solomon Grundy are all confirmed to be making appearances. Fish Mooney will resurface as well, and there's a lot of speculation that Jerome and/or The Joker could come sauntering out of Hugo Strange's lab as well.

Gotham is currently in production for its third season, which will premiere on Monday, September 19, 2016 at 8 p.m. ET/PT on FOX.