It's actually litterally true. https://www.vatican.va/archive/compendium_ccc/documents/archive_2005_compendium-ccc_en.html#The%20sacraments%20of%20Christian%20

It's actually litterally true. https://www.vatican.va/archive/compendium_ccc/documents/archive_2005_compendium-ccc_en.html#The%20sacraments%20of%20Christian%20initiation https://www.vatican.va/archive/compendium_ccc/documents/arch... 283 > Transubstantiation means the change of the whole substance of bread into the substance of the Body of Christ and of the whole substance of wine into the substance of his Blood. This change is brought about in the eucharistic prayer through the efficacy of the word of Christ and by the action of the Holy Spirit. However, the outward characteristics of bread and wine, that is the “eucharistic species”, remain unaltered. Edit: It's a catholic thing, and it's very silly (other denominations say its symbolic)