Fluid and glass-like distortions can be achieved with the Gravimetric function. It works by summing up the "mass" of the heightmap around each pixel and distorts it to the appropriate direction.

How the distortion looks like is highly dependent on the employed heightmap. Image 2 for instance was created by using another texture (which was set as Source Texture) as heightmap source. The Generator/Water function was applied to that texture beforehand. In contrast, Image 3 and Image 4 were rendered with the Use Mask option enabled.

Increase the Pre-Smoothing parameter to create bevelled and smooth distortions.

The size of the computed neighborhood is controlled with the Radius parameter. Increasing this value results in smoother transitions, but also in a greater distortion strength.

This can be compensated with the Amplify value. It directly regulates the distortion amplitude.