What is a Blue Raspberry?

okay... so the other day i was having a popsicle... then i was like, "blue raspberry? what's blue raspberry? is it like an easier way to say blueberry/raspberry combo, or is it an actual thing?" i've seen a little picture of it on snacks as an actual blue raspberry... i've heard that it's real and just really hard to find... can someone please tell me... is a blue raspberry a real fruit? if so, why don't they sell them in the store? [idkk if location counts, but i live in new england if that helps at all]... if it's not real, then what is it? a combination of some sort? please help me!! i thought i was extremely retarded for not knowing... turns out, nobody else knows, either... which made it harder for me... lol okk so thanxx - kaitlyn