That foamy plastic stuff that's found in takeout food containers and coffee cups is called polystyrene.
While the material is cheap and fun to dig your nails into to carve out a smiley face, the benefits stop there.
Unfortunately, it's "probably carcinogenic", disintegrates into microplastics, and is made from fossil fuels. Plus, you guessed it, it can't be recycled.
But San Diego and Los Angeles just voted to ban them for good!