Other than the background, this image is done with maths. I made a 3D fractal with Mandelbulber2. I then applied a Gimp MathMap animation filter and modified the expression formula. You can do this with MathMap in real time and come-up with a whole new expression formula. If you are familiar with Mathmap try swapping a single 'x' or 'y' value in the expression box and test it out with the 't' slider.
It's normal for people to regard 3D fractals as infinite because without a bailout sequence they could go on forever. MathMap is based on it's own maths language and the existing filters can be further developed by anybody. So it's possible MathMap is also infinite.
MathMap is up to 18 years old but is still being developed by enthusiasts.
https://github.com/schani/mathmapIt's much easier to compile now and binaries are available.
Here is a webm version of the above animation:
https://gfycat.com/MatureRigidBlackbird