Hi @dharman Can you try again (perhaps with the latest build of Hops). I just tried using https://github.com/mcneel/compute.rhino3d/raw/master/src/hops/definitions/SpikeyThing.gh as my path and everything worked as expected.
Can you confirm that your rhino.compute instance is working? If you go to File->Preferences->Solver, on the top right you should see the Hops Preferences. You should see a checkbox that says
Hide Rhino.Compute Console Window. If that is unchecked, you should see a new console application appear in your taskbar (you may need to restart rhino/grasshopper for this to take affect). Do you see any errors or warnings in the console application?