diff --git a/src/spectator/dummy_example.cr b/src/spectator/dummy_example.cr
index 6b6366a..c941635 100644
--- a/src/spectator/dummy_example.cr
+++ b/src/spectator/dummy_example.cr
@@ -16,7 +16,7 @@ module Spectator
 
     # Dummy run that does nothing.
     def run_instance
-      # ...
+      raise "You shouldn't be running this."
     end
   end
 end