I highly doubt it would be illegal. Like the other person said, if it's trespassing then yes, its illegal, but most cemeteries are public places so if you get caught doing whatever it is you plan on doing, you'll just be asked to leave. I think you should dress as a grim reaper, though. It seems much more appropriate for a cemetery setting
tell me more of this plan
You can be asked to leave. If you do not then it can be considered criminal trespass.
if the cemetery has a no trespassing sign then you could get into trouble and the officer will most likely seek to evaluate your mental health
The only part about your plan that might be "illegal" is if you were trespassing. If they ask you to leave, you have to leave. Trespassing is usually a B misdemeanor, which means you go to jail instead of just get written a ticket and sent on your way.
It's not illegal technicly it's just riding a bike
It's stupid but not illegal.