noun, expression
one-track mind; person who always does/says the same thing
Jocular wasei-eigo phrase. Often used for someone who repeatedly tells the same kind of jokes or acts in a predictable way.
wasei-eigo (Japanese-coined English), from very special one pattern
彼はいつも同じギャグを言う、まさにベリースペシャルワンパターンだ。
He always tells the same joke—he's the very definition of a one-track mind.
またその話？君は本当にベリースペシャルワンパターンだね。
That story again? You really are a one-trick pony.