When they are around me, they are somewhat difficult to detect as they do not radiate energy from their soul like a human or angelic being. It’s like a piece of furniture with no life energy.
However, when they get close, you get real cold. Actually chilled to the bone like a blast freezer as they suck your soul energy.
I experience this same cold feeling to a lessor degree when I’m helping people cross over at death due to their soul borrowing my energy until they connect to the Light of Heaven.