Fake capes?

[ChrisXY]

The right one is super stretchy and looks kinda fake. But what about the left one? How to identify fake capes?

[Lyichir]

Hard to say, especially since both look quite frayed (likely due to heavy wear, whether real or not). Lego has varied the material of capes over the years as well, with a firmer, more starched material used in the past but a stretchier material used for some recent sets in themes like Super Heroes.