The Replica copies a player's actual Minecraft skin and wears it. It shows up looking like you, or your friend, or whoever's closest when it spawns.
It won't fight you right away. It just watches — standing off in the distance, staying just out of reach. You'll see it out of the corner of your eye and by the time you turn around it's gone. You start second-guessing whether you actually saw something.
Hit it, and that's what sets it off. It stops hiding and turns into something rotted — same face, wrong movements, eyes that glow, and it comes after you and doesn't quit.
That's basically the whole mod: something wearing your skin, deciding when it's done pretending to be you.
This mod is still in Beta so expect bugs, they'll be fixed in later updates.

