To help me identify it, please tell me:
* Where did you see it? (Location, habitat, etc.)
* What was its approximate size?
* Did it have any other distinct markings or features? (Stripes, spots, horns, etc.)
* What did it look like when it was moving? (Fast, slow, flying?)
With more details, I can provide a better guess or even point you to a resource that may help you identify the beetle.