Weird squishy, plastic sealed thing.

I was out at the thrift store bins and there were a tub Of miscellaneous objects and old packages. There were notebooks, decorations, literally anything you could think of. I just caught a glimpse of this and I had to know what it was. I asked the cashier and he was so confused by this object that he let me have it for free. What is this?????????? Fuuuuuck