Those awful ones they used to sell in the elementary-school cafeteria? With the eerie vanilla pseudo-ice cream center that melted into aerated slime, as opposed to actual ice cream? The processed chocolate substance that was neither crunchy nor chewy, in a cookie kind of way, but soft, and vaguely squishy, and would stick to your fingertips if you held it in the same place for too long?

Yeah, these.
(Should I be reading something into the fact that this image was supplied by the National Cancer Institute?)

I can remember eating these as a kid, on the rare occasions when I'd get one from a third party or scrounge together enough change to buy one on the sly (my childhood home was a house full of "ingredients", but no "food", and trying to get my mother to let me have so much as a cookie or candy bar usually involved negotiations that made the Reagan/Gorbachev summit meeting in Reykjavík look like a couple of guys getting together for beers). Tearing off the weak paper and eating the frosty-cold sandwich bite by bite, trying to keep the ice cream from compressing and oozing out the sides. Licking off the melting ice cream around the edges to keep it from leaking all over my hands. Deconstructing the sandwich by eating it layer by layer: first trying to peel off the chocolate sandwich layer in one full piece, then eating away the ice cream in the center until all that was left was a soggy chocolate sheet that could be folded up and consumed. Peeling off all the paper and licking around the sandwich, denuding the ice cream center until it was just two slices of chocolate material, one atop the other. Good times.