The Eucharist is a symbolic meal when Christians eat the body of Jesus symbolized by bread and drink the blood of Jesus symbolised by wine. Didn't you always think cannibalism is wrong?
Different Christian Denominations have different beliefs about exactly what happens during the Eucharist and were prepared to kill and die for their particular version of the Mythology.
See also
- Roman Catholic Eucharist
There is a good and a a bad side to Christianity, see the category page