It is known that one peculiarity of Catalonia is the scatology - and it's always fun to explain. I don’t know exactly the origin of this poop culture but I will explain you a little bit of the "Caga Tió".
He is a wooden log with a smiley face painted onto one end. "Caga Tió" also wears a traditional Catalan red hat as shepherd and is basically the Catalan equivalent of Santa Clause. "Tió" means "uncle", however it also means "log" (Holzklotz) - and "Caga Tió" translates to "poo log" or "poo uncle". In the beginning of the story he only brought turrons (Süßware) but now he brings also small gifts. You have to beat "Caga Tió" with a stick to make him poop presents!
The kids take care of "Caga Tió" from the 8th of December to Christmas Eve. They cover him with a blanket to keep him warm and feed him with oranges and sweets. The more they feed him, the more Christmas presents he will “poo-out” for Christmas. After the Christmas meal, the children sing a song and hit him at the same time to make him poo.

"Caga Tió, Tió de Nadal,
no caguis arengades
que són massa salades,
caga torrons que són més bons!
Caga Tió!"

"Caga Tió, Christmas Tió
Don’t shit harangues
because they are too much salty,
Shit turrons because they are better!
Caga Tió!"

After that the kids look in the blanket which has been keeping "Caga Tió" warm for the last few weeks, to find their Christmas presents. If you have been a bad child maybe you will find carbon (Kohle).