All good Catholics are familiar with how St. Dionysos is venerated by ripping small mammals to bits. And how the saint day of St. Jupiter is celebrated by dressing up as waterfowl and domestic animals and then trying to get dates. St. Thor is the patron saint of blacksmiths, venerated by collecting His comic book. As for the reliquary of St. Hermes, don't even ask.
Of all the all the pagan borrowings, of course, Santa Claus is the most obvious. His celebrations involve hanging stuff from trees. He knows if you've been bad or good.
Just ask yourself, do you ever see Santa Claus and Odin together at the same time? Think about it.