If it is siphoning or sucking the power or life out of something or someone and then redepositing that power somewhere else, maybe you can use the stereo field or front to back depth cues to suggest the energy is moving from one place to another.
Is this for a game? Or a video?
What's the playback medium? You might do things differently on a smartphone as compared to a home theater with 7.1 surround sound.
Stereo field stuff can be as simple as adjusting the balance with a pan pot, or you could go crazy if you have surround.
Depth cues include EQ and reverb tricks.
If this is a sound effect that will be paired with an image, then the context of what is happening on screen will color the listener's perception of the sound. You could foley in the sound of someone cutting up a zucchini and your audience will think that's what a magical siphon sounds like in this particular world.