We are thinking of having a ghostly figure walking around the museum in Hepto, and implemented a shader for this ghost (so called for convenience).
As for the requirements, we would like to create a material that has an indeterminate shape so the outline is unclear, a translucent background that looks distorted, and a grain of light that floats around.
For the blurring of the outline, we set the shader setting to transparent and used the inverse value of the Fresnel effect node for the alpha value.
In the simulator on the PC, this makes it thinner as it goes to the surroundings.
But when executed on the iPad, it does not display well and the surroundings become bright.
The Fresnel effect parameters are also applied to the background distortion rate, which works well. There seems to be a problem with the alpha settings. Continue to investigate.