The file
A square of peanut butter on a cookie base, dipped in chocolate. It sold well, it had a big ad campaign, and it disappeared anyway. The most-repeated explanation, from a former Mars executive, is that the owning family didn't like peanut butter.
Whatever the reason, PB Max is the discontinued candy people describe most precisely, right down to the crumbly base, and it's the one that gets the most "why?" — because there was never a good answer.
Sources: Wikipedia — PB Max
