It sounds like you're talking about time travel. These "worms" are called "worldlines". Spacetime is not simply R^4. You can rotate in the fourth dimension--this is just acceleration. But you can't accelerate enough to turn around and bite your own tail because rotations in the fourth dimension are hyperbolic rather than circular. You can't exceed or even reach light speed. There are solutions to General Relativity that contain closed timelike curves, but it's not clear if they correspond to anything physically realizable.