Partygeist
The spirit of a raging partier, a legendary party animal who refuses to move onto the afterlife. Not a hostile spirit, but definitely aggravating since all it does is drink booze and get hungover, can ghosts even get hung over?
The bopping music, the stench of Jager, the undeniable amount of ectoplasm everywhere. It could only be the work of a Partygeist.