Gather up a bunch of old keys to create unique invitations. Paint each key with black nail polish or coat them with black spray paint (in a well ventialted area). Using red ribbon, tie a card containing the party specifics to the keys - inviting the guest to a complimentary stay at the Hotel Transylvania. For an extra funny nod to the movie, add 100 years to the Birthday child’s age. If you are hosting a slumber party, have their invitation include "one free night’s stay".
This is a great time to re-use all of your Halloween decorations:
Hang Spider webs and dangle cut out cardboard letters that spell Happy Birthday from the webs.
Add party hats to all your goblins and goulies.
Cover tables and chairs with white sheets and add paper cut outs of giant googly eyes so they look like ghosts
Place candles around the room. Use flameless candles if you have young children.
Draw funny, shrunken head faces on small, white cake plates. Hole punch the top, string a ribbon, and hang from doorknobs all over the house
Take small fallen branches and mount them in buckets of sand to create an evil forest.
Hang lots of black paper bats on fishing line from doorways and light fixtures. Or tape them to a helium balloon string so they look like they are fluttering around the room.
You can make a fast bellhop hat using a round oatmeal container. Remove about 4 inches from the bottom of the container and cover with red or black duct tape. Add a strip of silver or gold tape around the edge. Punch two holes on either side and string some elastic to make it stay.
A simple standard cake that says the age plus 100 (example 106th) birthday is a fun idea.
Cupcakes with spiders frosted on them could be fun too…or check out some of the fun food websites for Halloween treats.