Chapotraphouse

There's a good novel called Translation State by Ann Leckie you should read.

Technically you should read the Imperial Radch trilogy first since that establishes a lot of back story, but it features a species called the Presger who don't even seem to conform to euclidean space, so much so any human who ends up in close proximity to them is assumed dead, even if they show back up looking fine, it is assumed they are a facsimile created by the Presger.