If you look at the picture that shows all of the ships that were sunk in the Burmuda Triangle, you can see a large figure in the tunnel. (I can't post a link to the picture at the moment.) I think that might be the Atlantis boss. I don't know. I'm just pointing things out and speculating. --- Remember those in prison as if you were their fellow prisoners, and those who are mistreated as if you yourselves were suffering. Hebrew 13:3 (NIV)
It's a shadow of a biped, IIRC, stretched by a lightsource laying on the ground.
The boss of the stage seems to be a giant serpent that sunk all those ships. --- 2% of GameFAQs users have this in their signature. If you're one of the 98% that doesn't, copy and paste this into your signature.