That'll teach you to

Chandler has a bite in his mouth and can’t come back.
Then Monica said; "That’ll teach you to lick my muffin. "

This is from Friends. Chandler took Monica’s muffin and lick it when he was
asked to give it back to her. So she was upset about it.

Here, I don’t know why “will” is needed in this sentence.
Because Chandler tried to speak up but because of the muffin in his mouth
he couldn’t speak right away, he needed to swallow it first.
So “That” means this situation and it tought him he shouldn’t have licked her muffin, right? So I think this should be past tense, not future tense.

But if you think Chandler shouldn’t do that in the future too,
“will” might be appropriate here though. I’m not sure.

Anyone to help me? :slight_smile:

‘That’ll teach you’, besides being a fixed phrase, uses the ‘will’ of assuredness.

Will - 6. used as an auxiliary to express probability or expectation on the part of the speaker: that will be Jim telephoning.

Oh, I see. Thank you! :slight_smile: