Is there a word for taking something that's meant tongue in cheek seriously? For example trying to prove someone wrong after they taunt you by saying “You couldn't fight your way out of a paper bag”.
You might think of this as a visual pun:
visual pun When a phrase which is usually used as a metaphor is instead done, and shown as being performed literally.
In one of the The Naked Gun films the main character, Frank, says to a bartender "give me the strongest thing you've got", provoking a VERY muscular and oily man in a thong to walk in, flexing his arms. Frank decides against this, and instead asks for a "Black Russian". The bartender just looks at the camera and shakes his head.