get (any) ideas

To have thoughts or schemes about taking advantage of a particular person or situation. Often used in a negative imperative. I know you're excited that your parents are going out, but don't get any ideas—I'll be here watching you all night. We have an extra guard posted outside in case the prisoner gets any ideas. Don't get any ideas just because I'm a substitute teacher. I know Mrs. Smith expects all of you to be on your best behavior in her absence.

get (or give someone) ideas

become (or make someone) ambitious, big-headed, or tempted to do something against someone else's will, especially make a sexual advance. informal