Comment by geerlingguy

There's an important distinction between the 'substance' and the 'accidents' (outward characteristics), that matters a lot in Catholic theology.

Some deeper discussion around Aquinas' philosophy on the difference: https://iep.utm.edu/thomas-aquinas-metaphysics/#H4

But I'd say any Catholic who believes in the Eucharist would admit, yeah, it's a bit of an odd thing, especially by today's standards, to consume the blood of a sacrificed animal.