There are many methods of creating Tentacle VFX. I found a method that works really great for Thruster effects. The technique I explain in the video can perhaps also be used as a technical approach for smaller tentacles.
Although this is not the only possible solution. We could solve this by taking a point at a distance away from the emitter source and use the system velocity to add some drag and to play with the stiffness. We can then interpolate a bezier between the source and end position to construct a nice curving ribbon shape with ‘Fake’ physics. This method can also be used for a torch fire effect.