put a fake snake in their bedroom and say you have a snake problem.
It's important to address the situation respectfully. You can try having an open and honest conversation with your grandma about how her behavior is affecting you. Setting boundaries in a gentle manner and expressing your feelings could help create a better understanding between you both.
Ignore Them
You get rid of a annoying flea mite by hitting it so hard that it starts to cry and cry
well it really depends why she is being annoyng lol
just go away
throw it off a skyscraper, won't be annoying after that.
Try being a less annoying niece.
Say that you love him. He probably has a crush on you.
Punch her in the tummy.
Don't use that company or store
say can you go away because you have been annoying me all bloody day you annoying idiot
Sending her to an adult care facility would be the kindest option.