Age 2 Don't worry, your toddler is not only normal, she's also very creative. Her burgeoning imagination fuels this wonderful fictitious creation, someone who accompanies her as she explores the world.
Imaginary friends are also one way children learn to make distinctions between good and bad.
If she passes the buck, take her explanation at face value and help her clean up, but gently remind her of the house rules. Try not to make a big deal when she mentions her imaginary friend. There's no reason to make her feel funny about talking to someone who doesn't exist. On the other hand, if you go all out to include her imaginary friend in your world, you may have her pal overstaying his welcome, or your daughter may feel as if you've co-opted her buddy. See other parents' comments on this topic.