Doppelgänger

[formal basin]

A Parasitic Monster who can steal the appearance of a player. It has 3 forms: Invisible, Physic and reveal.
He has a passive when he can room the map freely but not doing anything.
Invisible: He is invisible, he can't see other player. He can hear them but the sounds are muffled.
It can go into his "physical form" for 60 seconds, he is physically present in the room but he is invisible to the players.
He needs to choose a player before he is able to enter his physical form. He will only hear its target very well and the target will emit footstep when the 60 are over.
2.Physical/stealth: In this form, he steals the shape of the target (without killing it), he can move and act like a player. He can interact with doors and switch light, but not with battery, pills, keys or puzzle. He can run, flashlight and is even able to talk (but that'll reveal his identity). He can stay in this form for 60 seconds as well.
Reveal: When he stays about 30 seconds into his physical form, he can finally reveal his true form.
He will transform automatically when he stays more than 60 seconds into his second form.
He will make a lot of noise, his appearance will change and will be slow.
After that, he will have brief burst of speed of 4 seconds and will be able to attack.
He can stay in this form about 10 seconds.
After that, he will return into the invisible form.

PEKS IDEAS ARE BELOW !

Idea of Perks:
1.Bodysnatchers: When he kills someone, the victim won't emit any sounds and his body will disappear. The doppelganger will take his appearance and return to his physical form.
This physical form will stay 90 seconds instead of 60 and can enter to the reveal phase whenever he wants.
2.Listening: In invisible form, he can activate listening.
This ability allow him to be able to hear all the vocal conversation of the survivors.
3.Lure: He can send a Lure in the invisible stage. The Lure looks like a player, the Lure will search and follow players. Lures have a lifetime of 60 seconds and can be killed when a player point his flashlight on him for a certain amount of time. When they died, they will play the transformation animation, then they disappear.
4.Stealth murder: His reveal form will be replaced by a stealth attack. Only his face will bedistorted and he will be slow. He needs to charge this to the maximum to deal the damage. When he applied his attack, he will return into the invisible form.
5.Hide-and-seek: when he is in his physical form, he can hide into a props. He can only go out his hiding place after staying he stay about 45 seconds into his physical form. When he goes out, he transforms itself into the reveal form.

[last fern]

I really want a doppelganger monster, but I find difficulty in how the game works right now.
How it would work in a 1v1 match?
What stop the monster from just staying close to a survivor, transforming and killing it?