Student corpora and Catholic student associations award a diploma to their new members in obtaining their membership. The word bull is named after the leaden seal (bulla) that was traditionally appended to the end in order to authenticate it.
As you can read above, a bull is super awesome! Once you have signed up for this event, the Assessor I will make a handmade bull for you. You can obtain it at one of the General Members' Meetings or after the October General Members' Meeting in the P.S.-boardroom. It is very nice to hang the bull above your bed!