We made this Ocean in a Bag Sensory Craft last summer. It was a huge hit with my little guy and a fun experience.
My son squeezed blue hair gel that my hubby didn’t like into a Ziploc baggie. You might also be able to find a bottle at dollar stores. He added water animal foam stickers, beads, and glitter.
I sealed it and then put it inside another Ziploc bag in an effort to avoid any messes. We made a similar activity in a class when he was 1 year old and the bag broke. It oozed gel everywhere so I definitely recommend putting it in another bag with the zipped end towards the bottom.
My little guy had fun squeezing and poking his little ocean!