Mother-in-law taught my toddler to scream.... Now we can't get her to stop. Please help me!

My mother-in-law likes to do things that push our boundaries and limits. At dinner a few weeks ago (at her house) she decided it was "So cute!" that our daughter did this shriek. We told her to not encourage that, but she kept saying things like "Let's test your lungs! Ahhhh!" And "Louder louder LOUDER! Ahhhh!" and shrieking too. My husband and I ended up leaving dinner but yikes.

The whole way home my daughter screamed randomly in the car. She did not stop. Since then she just screams and shrieks randomly. She even goes "Louder louder AHHHHH!"

PLEASE tell me this too will pass on a few more days. It's already been three weeks and it feels like it's never going to stop.

Edit: my daughter is 2.