The Count Lucanor (UP)

In the depths of the castle, the room with the golden emblem you need will have a worm you will automatically obtain once you enter it. A little while later, you will enter another room to get water for a plant and the worm will make itself known again. Once you've watered the plant, go back to the character by the save fountain and get a rusty key from him.

Take the rusty key back to the area where you got the water and enter the house. On the table you will find a cake – equip the worm and use it with the cake to unlock this trophy. Doing this is setup for both Crown jewel and several of the ending trophies.