wait-so communion is vampirism and cannibalism, literally. bread and grape juice/wine just never made that jump for me. Sitting down and having communion, in memory of his blood shed for you, and eating the bread, in memory of his body broken for you, doesn't induce thoughts of eating and drinking Jesus, literally. Besides, I thought this was at the end of the sabbath day feast, something no churches I know of celebrate, sadly. This is called "majoring in the minors". If you believe the basics, and lump the grail on top of everything, then I'd say this belief is innocuous. If you believe the basics, but only if it's all vampiric cannibalism, then you may want to meditate on what the bible says more, and not so much on speculation.
i think that the bible is kind of "layered" in that i believe it can have different meanings to different people at different times regarding different things. the same scripture can have various different meanings and reveal various things to various people at various times, and that all of those things are true, even though they are not the same at all. in the case of communion, i would think that there is a meaning regarding end times events that is very different from the meaning regarding the crucifixion that took place two thousand years ago.