How to get the ghost head accessory:
1. Go to Fairy Godmother npc in Megalopolis (warp to event map)
2. Get the event quest from Rachel
3. Complete the event quest
4. Open Rachel's Gift Box
5. Take the ticket inside to exchange for the ghost head acc
Voila, your very own spooky buddy!
Pretty sure it IS permanent once fused with something else CookiesNCream, like the other timed equips that have been fused with things.
"The sad part about a good series ending is feeling like there is so much more that could be written."-K.M.