The Labs Mandelbulb Generator is part of the FREE and open-source toolset in Houdini called SideFXLabs.
This SOP node generates Mandelbulb geometry using OpenCL.
For more information on SideFXLabs and how to get the tool visit: https://www.sidefx.com/products/sidefx-labs/.
Here’s a quick video to show the node in action.