expression, godan verb (-ru)
to come up with a bizarre idea; to have a sudden whacky thought
A set phrase meaning an idea so strange it seems to come from beyond the ordinary. Often used when someone proposes something wildly unexpected or eccentric.
彼は奇想天外より来るような発明を次々と考え出す。
He comes up with one bizarre invention after another.
An adjective meaning 'fantastic' or 'bizarre'; the full phrase 奇想天外より来る turns it into a verb phrase meaning 'to come up with something bizarre'.
A set phrase combining 奇想天外 (bizarre, fantastic) with より来る (to come from), literally 'to come from the bizarre and fantastic'. The exact origin is uncertain, but it is used to describe ideas that seem to emerge from an otherworldly source.