na-adjective, noun
complicated and mysterious; intricate and bizarre
A yojijukugo describing something so complex and strange that it is hard to understand. Often used for plots, situations, or mechanisms that are both convoluted and eerie.
この事件は複雑怪奇で、真相がなかなか見えてこない。
This case is complicated and mysterious, and the truth is hard to see.
彼の説明は複雑怪奇で、何を言っているのかさっぱりわからなかった。
His explanation was so intricate and bizarre that I had no idea what he was talking about.