Your preschooler loves playing with her new best friend -- her imaginary friend -- but suddenly her good pal has started acting bad. Most likely, this simply means your child is trying out something new. "Having a naughty imaginary companion lets children explore what it means to be bad or reckless without acting that way themselves," says Marjorie Taylor, Ph.D., author of Imaginary Companions and the Children Who Create Them and a professor of psychology at the University of Oregon in Eugene.

Your child's "friend" is helping her make sense of what's going on in her real world -- like dealing with discipline and rules. But just because your child's buddy misbehaves doesn't mean she'd like to, notes Taylor. "Sometimes it's nice to be the 'good' person who gets to discipline someone else instead of being the one misbehaving," she says.

Here's how to indulge your child's creativity while reinforcing your rules:

Ask questions. If your child is screaming or hitting and saying her buddy is doing it, ask why. An imaginary pal can be your best friend because it gives your child a chance to tell you how she's feeling.

Use discipline. Your child is likely trying to figure out how much she can get away with. If her friend's misbehavior calls for it, use time-outs (or whatever discipline method you prefer). And if your child tries to pin the blame for her own bad behavior on her friend, deal with both of them.

Remind your child of the consequences for misbehaving. You don't allow your kid to hit, so the rule should extend to playmates, too -- real or imagined. Explain that if he can't behave, he'll have to leave. Chances are he'll live by your rules.

Call in an imaginary mom for help. Just as you might call the mother of a flesh-and-blood playmate, you can conjure this pal's mom to back you up. It just might work.

---