Storm in a teacup
tʃaɪniːzle̞tə tʃaɪniːzle̞tə nä ko̞ to̞ o̞ ɡe̞sänisɯᵝɽɯᵝko̞to̞ ɛs eɪ ɛs eɪ aɪ ɛn eɪ keɪ əʊ tiː əʊ əʊ əʊ əʊ dʒiː iː ɛs eɪ ɛn aɪ ɛs juː ɑː juː keɪ əʊ tiː əʊ
In Japanese 些細なこと[を]大げさにすること (sasaina koto [o] oogesa ni suru koto)
This is a descriptive phrase, not a direct idiom translation.
Example
"彼は些細なことを大げさにします。(Kare wa sasaina koto o oogesa ni shimasu.) - He makes a mountain out of a molehill."
