A test for things outside of spacetime
Representative Luna has given us a working definition of interdimentional as something that operates outside of spacetime. If I send myself information back in time then I already know it. If I send myself information forward in time that's just a time capsule. If something disappears and then something that appears somewhere else that looks like the first thing I can assume that there are more than one that looks the same. What test can you think of that would tell you that a UAP/UFO/USO is operating outside of spacetime?