What would be a fun game to play with babies and their caregivers during a swimming lesson?

I am a new swimming instructor and I have to write up all of my lesson plans. I am working on my first lesson plan now, for babies aged 4 - 18 months. I'm looking for a fun, easy, warm up game I could include in my lesson plan

Thank you for any suggestions!What would be a fun game to play with babies and their caregivers during a swimming lesson?I take my 3 year old to swimming lessons, we have been going for about 3 months... Our instructor starts the lesson by singing the wheels on the bus - except it goes the children in the pool they scoop their hands / kick their legs / blow bubbles / kick scoop blow.... Then we sing ring 'a roses and when we do the tissue, tissue, all fall down bit, we put the clilds face in the water for a split second... Then we sing hokey kokey and instead of ra ra ra, its splash splash splash.... The instructor then puts toys in the water (watering cans, balls, bath toys like fish, ducks, etc) As the children play, she works with each child individually... Throughout the lesson, she has the children sit on the side and kick their legs in the water, and stand at the side then jump in...