Shares a granola bar full of peanuts and lies and tells me there's no peanuts in it. RIP me.
Bring as many npcs in the room as possible; then wait for the social anxiety to make me lock up
Ask me about something I'm above average knowledged about that I'm also interested in, and then you can disarm the bomb, save the pricess, destroy my entire species before I'm done oversharing the introductory part or even its preface.
Exploiting my hubris.
I actually wrote out an outline for this back when I was making small videogames as a hobby. I never actually made the game, which was probably overly ambitious, which is fitting because it was a game about ambition and hubris with me as the villains (multiverse shenanigans) and a pair of scrappy teenage sleuths as the protagonists.
Cheese.
Either the edible kind or the repetitive-bullshit-but-it-works kind.
Intended method: three phase fight where the PC must break a magic shield before I get off a spell (DPS check). Breaking the shield releases a shockwave which either needs to be dodged or cancelled by an optional item (magic earmuffs). Failure to break the shield fails the fight, sends them to the room before (fuck you watch the whole cutscenes again)
Pacifist method: compliment me a couple of times and I won't know what to do with myself. I teleport away, leaving the key