The secret method for making Evangelion plugsuit anime noises has been revealed (and preserved)

The studio then had to decide on, and craft, the audio aspects for when characters were moving around in them.

With a handbag, specifically the handbag shown in the photo below, shared by current Evangelion studio and rightsholder Khara.

And to be clear, the photo shows not just the model that was used to create Evangelion’s plugsuit sounds, but the exact bag itself.