So if you don't know who Eclipse is, he's basically a mix of Sun and Moondrop (Like an eclipse, that's why he was named that) and he was an easter egg in SB. Anyway, I'll leave a pic of him in the comments.
Back to my theory. Since Chica looks like she's melted in some kind of way, that goes back to the Fire and ScrapTrap ending of FNAF SB. Since this is basically the runner-up to Security Breach (I think) then that would go with that ending. All the animatronics were trapped inside the Mega PizzaPlex, including Sun/Moon. Maybe... they merged together during the fire, and created Eclipse? Idk if we're going to see him in the game, but that will be awesome if he was!
