Work Text:
After Aizawa got knocked out at the USJ attack, a villain he had fought used a body stealing quirk to be a spy at UA for AFO. Aizawa 'woke up' in the hospital to his best friend talking to his body and he is trapped as a ghost. The only one that can see him is Izuku (unknown 'death vision' quirk) and Hizashi is suspicious of 'Shouta' because he is acting differently but he can't explain why.
Izuku has to work with GhostZawa to convince Mic what's happening while avoiding FakeZawa finding out Izuku knows.
Izuku would have to find a way to tell Mic first so they can both tell Nedzu. A student alone isn't much evidence but if he brings a teacher, and the man's best friend, it has more leverage to it. The issue is trying to get Mic alone when Fakezawa is always with him because he is hurt and Mic is helping him.
Izuku might use some English homework as an excuse (Mic knows he is fluent from his dad being in America) and write a note in English about Aizawa not being who he says he is.
At a later point in the fic Mic is in a meeting with Nedzu about what to do when they get the alert of a student in the training grounds without permission and the cameras show Izuku running scared. Mic rushes to help as Nedzu calls the other teachers to help stop Fakezawa, the fake has all of Aizawa's skills so they will need help and they don't want to hurt the body.
By the time Mic gets there maybe Izuku is caught or just really hurt with Fakezawa over him. Izuku still can't use his quirk safely yet, so he can't use it without hurting himself or Aizawa's body. Fakezawa has a knife and the capture scarf so he could either stab Izuku or be strangling him with the scarf when Mic knocks him off and fights him.
Mic is the first one there having to fight his best friend's body as his student is hurt in the ground. GhostZawa is trying his best to comfort Izuku until help arrives. He grew close to Izuku in the time stuck as a ghost with him, saw how lonely he was at home and became a father figure to Izuku.
Notes:
1) Present Mic is suspicious almost immediately , you don't hang out with someone for over 15 years and not notice all the little details about them. If asked what tipped him off Mic might say 'his walk wasn't right' or 'he held his cup wrong', small things the body stealing quirk would tell the user the body acted like but easily missed in learning the rest of the identity. Mic felt the vibes and the vibes were wrong.
2) Death vision quirk: Grants the user the ability to see the dead. The user cannot hear the dead but body movements or JSL can help this issue. The dead appear to be ordinary people, no injuries to be seen or cause of death. They just appear pale and sometimes blurry under direct sunlight.
The death vision quirk was unknown because Izuku can't tell the dead and living apart.
3) Body stealing quirk: Allows the user to swap bodies after 'pushing' the original soul out. Grants the user the memories of the new body in order to blend in more and not attract suspicion. Does not allow the use of the body's quirk beyond physical mutations.
(Due to the injuries at USJ, everyone just thinks Aizawa just lost the use of Erasuer.)