CHUD Tools are a set of profiling and performance tools for use in applications development on the Mac. The package includes a lot of things, such as DTrace, OpenGL Profiler, and Instruments. Shark in particular is a favorite tool of mine; it's a spectacular profiler with a great interface.
I accidentally stumbled across an application called CHUD Remover that claims to remove CHUD files. It lives in /Developer/Applications/Performance Tools/CHUD.
