Traditional Catholic Mass includes the rite of communion, a practice when worshippers consume the metaphorical body and blood of Jesus Christ. The priest blesses bread and wine which, according to the ritual, turns the bread and wine into Christ’s body and blood.
All masses were conducted in Latin before Martin Luther initiated the Protestant Reformation in 1517. In Latin, the phrase which transforms the bread into the body is “hoc est corpus.” Translation: this is the body. A bastardization of this phrase by non-Latin speaking worshippers turned into the phrase “hocus pocus” known today.