When a player stumps you #1

Not a direct quote. More an essence of things that have happened at games I've run at events.

#Intro spiel is all about "this is a low magic fantasy 1200s medieval setting and you are a farmer"

Later in the game.

Me: What do you want to do

Player: I want to shoot him with my gun.

Me:..... This is medieval fantasy, you don't have a gun. And you are tiny.

Player: Yeah?

Me: When did you even get a gun.

Player - Goes into detail of how, using logic and creative tie in, citing accidental time travel or engineering genius.

Me: Awesome. you have 3 bullets and will have to deal with the backlash of having such strange tech.

Or another situation.

Me: And they deal 15 damage.

Player: Oh I quickly make a healing potion.

Me: What?

Player: Oh I make a quick healing potion. Like... I'm an alchemist and um... my grandma once told me that grass and wine makes a healing potion.

Me: Sure... you make a "healing" potion, just as your grandma taught you.

Player: How much do I heal.

Me: Whilst making your healing potion, the orc cuts your head off.

I am largely super loose with the rules. Especially if players haven't read the rules. And you get players who are like "Oh you are running this game so... your word is final." And some of them question my calls. And that's wonderful. But then you have players who are like "I am Harry Potter and I have a laser gun and a bag of 500 things" And I pause and think "I guess they are having fun but also..... no. You can't come into a game with helpful rules and guidelines and just GM the game. It's in a similar category for me the players that instantly split the party. Like... if you wanted to play by yourself, don't come to a table with 4 other players.

I am slowly finding ways to politely guide these outliers back into the sweet fold of co op story telling. But I haven't found the holy grail yet.