Imaginary friend

My almost 3 year old has had an imaginary friend for the last few months. Her”friend” is actually her right hand and she has named it “frog”. And now her one foot is “butter”. Her imagination is running wild. But sometimes “frog” does bad things... it will knock over milk cups, pull her hair, mess puzzles up. Nothing violent.. but still a little worrisome. Does anyone have experience with imaginary friends and how to deal with them?? I’ll be bringing it up at her check up next month. Thanks!